Engadget Labs: The best mobile data carrier in America

When T-Mobile finally decided to join the 3G data card bandwagon earlier this year, we figured it prudent to grab a few sticks from the likes of T-Mob, Sprint, Verizon Wireless and AT&T in order to see which carrier provides the most bang for the buck in the mobile data arena. And trust us, it's about more than just uplink and downlink rates in 2G / 3G regions these days -- it's about figuring out which operator provides the coverage you need at the price you can afford, all while dodging those precarious overage charges and finding yourself out of luck when traveling overseas. Join us after the break as we delve into the deep, murky realm that is mobile broadband, and prepare to have your every preconceived notion about this stuff utterly destroyed.

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The cards

From the onset, we sought to pit the cheapest cards from the four major US carriers we could against one another. After all, performance at the bottom is a good indication of what you should be able to expect at a bare minimum. Furthermore, there's really no need to pay for a WWAN card these days; you're signing away your cellular soul for two years -- the least a carrier can do is toss you a card gratis. Furthermore, we chose only USB data sticks for two reasons. First, we wanted a uniform interface across the board, and T-Mobile only offers a USB card. Secondly, USB is far and away the most widely available connection, with not everyone moving to an ExpressCard-equipped machine just yet. It should be noted that none of the cards we tested had external antennas, so what you see is what you get. Without further ado, here are the combatants:

• AT&T: Sierra Wireless USBConnect Mercury, free after a $100 mail-in rebate and a 2-year data plan ($249.99 sans commitment)

• Sprint: Sierra Wireless 598U, $29.99 after a $50 mail-in rebate and a 2-year data plan ($249.99 sans commitment)

• T-Mobile: Huawei webConnect USB Laptop Stick, $49.99 after $200 instant rebate and 2-year data plan ($249.99 sans commitment)

• Verizon Wireless: UTStarcom UM175, $29.99 outright with a 2-year data plan ($79.99 sans commitment)

The testing

Before we get to the semantics, there's something you should know about mobile data: it's completely unpredictable. While one may have great coverage and throughput at home, heading down to South by Southwest or CES -- where towers are notoriously strained -- could throw a nasty kink in your upload plans. In short, there are oodles of variables when it comes to snatching and maintaining a solid WWAN connection, most of which you have little to no control over. A good thing to consider before buying one card over another is whether your actual smartphone has trouble with data. If you find that your carrier can't consistently provide solid data to your mobile browser due to overloaded towers (in an area that you frequent, obviously), you'll probably want to focus your attention on results of the other operators.

Put simply, we fired up each card on a Windows XP laptop, using a variety of urban, suburban and rural locales for testing. Currently, T-Mobile's webConnect card is the only one of the bunch that won't work on a Mac, though the carrier has been promising support "soon" ever since it debuted in March. To check download, upload and latency measurements, we used DSLReports' Flash 8 speed test, which has become somewhat of an unofficial standard over the years. We tested six separate locations a half dozen times, throwing out the outliers and coming up with an average that we felt was truly representative of our experience. We've got the full findings below, but here are the highlights:

• AT&T's download rates obliterate the other guys. Seriously, it's not even close.

• AT&T's upload rates are the strongest, though T-Mobile and Verizon held pretty close here.

• Each carrier's average latency was right around 150ms, which will undoubtedly make online gamers (snipers, in particular) weep.

• Sprint and Verizon's WWAN management software was far superior than that of AT&T and T-Mobile, and considering that T-Mobile's app won't run on a Mac yet, it gets yet another strike against it.

• As always, your miles (or data rates, as it were) may vary depending on location, network saturation, wind speed and amount of fairy dust in your pocket, but we're pretty confident these data are a solid guide.

• If you're used to thinking of upload and download rates in terms of KBps (much like you see when downloading a file in Firefox), here's the breakdown of that.

The cost breakdown

As we alluded to earlier, we attempted to snag the cheapest card we could from each carrier. Sprint does offer a few free-on-contract cards, though they only had the $29.99 (on contract) 598U available for loan. T-Mobile has a grand total of one 3G data card, which runs $49.99 on contract, and Verizon's cheapest card was the $29.99 UM175 that we tested. At present time, AT&T offers a couple of free-on-contract cards to choose from.

Contrary to popular belief, all four major US carriers offer capped mobile broadband plans to consumers. In other words, it's not unlimited. In fact, you'll only get 5GB of throughput per month before those nasty overage charges start to kick in, so you should go ahead and cast aside those dreams of using an AT&T data stick to replace your in-home cable internet service. We can't say we like the cap, but that's just the way things are at present time -- hopefully we'll look back in a year or so and laugh at the preposterousness of plans past.

So, here are the highlights:

• Every major plan runs right at $60 per month for 5GB of throughput.

• Sprint is the only carrier that avoids dinging you with an activation fee.

• AT&T and T-Mobile are the only two with true worldwide roaming support (GSM bands).

• International data roaming is absurdly expensive; you're infinitely better off just buying a prepaid data card in the country you travel to.

• AT&T offers the most data card options; T-Mobile offers the least (just one).

• Even domestic overage charges are pricey; don't buy a data card to act as your primary ISP -- this stuff is for backup / traveling only.

• Sprint will cut you a $9.99 discount if you bundle a data card in with a phone in a Simply Everything package.

The coverage

Coverage is a funny, finicky thing. And oftentimes, you can't even take those blotchy coverage maps as the absolute truth. For example, your data card can typically roam on partner networks if you find yourself in a remote location, so things may not always be as hopeless as they initially look.

Verizon Wireless Data Coverage

Based on native coverage from each carrier, Verizon Wireless (shown above) has the best coverage in the United States, with AT&T (shown below) close behind, although it's 3G service isn't available in many locales. Sprint follows behind them, though it's roaming network is quite vast; we should remind you, however, that your $60 monthly data plan only allows for 300MB of throughput while roaming, so that benefit is severely hampered. T-Mobile's US data coverage is borderline pathetic at this point, but considering that it just got into the 3G data card game a few months back, we'll cut 'em some slack now in hopes of seeing massive improvements in the near future.

AT&T 3G Data Coverage via Verizon Wireless Overlay (for AT&T's 2G WWAN map, click here)

We're providing coverage links for each carrier below to allow you to scope things out in the area you call home, but we can already say that T-Mobile probably shouldn't be your top choice at the moment. The anemic network and inability to roam domestically really kills it when compared to the other guys.

T-Mobile Data Coverage

Oh, and then there's the matter of international roaming. Without a doubt, the only cards for jetsetters to get are those sold on T-Mobile and AT&T's networks. These are the only two that operate on GSM frequencies, which is far and away the dominant technology outside of the US. In fact, only a few nations outside of North America have any significant CDMA coverage, so if you plan on spending any amount of time surfing in Europe, it's GSM or bust. That said, we actually wouldn't recommend selecting a carrier here in America based on how robust the international roaming options are. In every scenario, it's drastically cheaper to head overseas and pick up a prepaid data card from a local carrier -- like O2 in Germany, for example, which offers a USB data stick with a month of unlimited usage in the country for just €69.99 ($96). A Benjamin for unlimited usage in Deutschland, or $20 per megabyte? An easy choice, obviously. Of course, it's nice to have the option of hoping online in any corner of the world if necessary, but with the growing pervasiveness of WiFi, we certainly wouldn't rule out the CDMA carriers here in the homeland just because of that.

Sprint Data Coverage

• AT&T Coverage Map (click 'Data')
  

• Sprint Coverage Map (click 'Data, Email and Multimedia')
  

• T-Mobile Coverage Map (click 'Data Coverage')
  

• Verizon Wireless Coverage Map (click 'Broadband & V CAST')
  

Other considerations

As with most everything in life, the devil's in the details. Sure enough, there are a few non-glaring things to take into consideration beyond the obvious when it comes time to select a WWAN card, so we'll do our best to cover those here. First off, Mac users should avoid T-Mobile's card -- at least for now. OS X software has been "coming soon" for far too long, which just doesn't rub us the right way. Also, we had a mess of a time getting Sprint's application to play nice with OS X 10.5, though OS X 10.4 had no problems with it. Possibly a one-off thing, but hey, there it is.

As we stated earlier, Sprint and Verizon Wireless' connection management software was easily the best. AT&T and T-Mobile could really use some work on the application end; both apps got the job done, but they certainly aren't robust in any way. Sprint's portal even provides easy links to GPS applications, speed tests and all manners of extras.

Flexibility wise, T-Mobile and AT&T are superior. If you run across a pal with an AT&T data card, you can just pop their SIM in your stick and use that monthly allotment if need be, and the same goes for T-Mobile. Also, T-Mobile and AT&Ts cards are far more useful overseas due to their GSM nature, but again, we don't expect you to take advantage of that too often with the international roaming rates being as ludicrous as they are.

As for card design, all four of the units that we tested were pretty average. We will say that Verizon's UM175 was our least favorite, as it was definitely the largest and had a rather strange spring mechanism for covering and uncovering the USB head. We greatly appreciated the microSDHC slot on the webConnect and the microSD slot on the USBConnect Mercury / 598U. As you could likely guess, the VZW unit was the only stick sans some sort of expansion port, and unfortunately for Big Red fans, the carrier doesn't provide an awful lot of choices when it comes to WWAN cards.

As for deals, you can trim $9.99 per month (in theory, anyway) from your monthly data plan with Sprint should you also buy a smartphone and snag the $149.99 Simply Everything plan. AT&T users with a LaptopConnect plan of $59.99 and up will receive complementary AT&T WiFi Basic access at thousands of the outfit's hotspots around the country. Similarly, those who buy a T-Mobile webConnect card will get unlimited WiFi throughout the company's 'HotSpot' network.

Finally, we'd be remiss of our duties if we didn't point out a little solution by the name of MiFi. The Novatel-sourced device is essentially a pocket-sized EV-DO router that creates a WiFi hotspot for any and all WiFi-enabled devices to tap into. Sadly, the plans that accompany this device -- which is only being made available on Sprint and Verizon Wireless for the time being -- are still capped at 5GB. In other words, this thing makes it a lot more convenient to dip into those overage charges each month. Still, it's a viable option for those who can live with a unit larger than a thumb drive (and dig VZW / Sprint), though the up front price of $99 (after rebate and two-year agreement) is on the high side for this discussion. Hey, you pay for added functionality.

Wrap-up

Sadly for consumers, we can't compare these options on monthly throughput allowance or monthly rate plans. In a fashion that only a colluder could love, the big four here in America all have matching monthly rate plans with matching monthly caps (5GB). So much for choice, right? In our view, it's also somewhat frivolous to compare the offerings on international compatibility considering that you're always better off just picking up a prepaid option from a local operator upon your arrival overseas.

So, what are we left with? Raw speed figures and coverage, really. Based on coverage alone, we'd select Verizon first (from a national standpoint) and AT&T second. Naturally, you'll need to visit those links in the 'Coverage' section to see which carrier is superior in your neck of the woods. Unfortunately, Verizon was the slowest of the bunch (albeit not by much), and AT&T was the victor by a country mile in terms of Kbps. If it's speed you're after (and really, who's not after speed?), we can't help but recommend AT&T -- if you're within one of the carrier's limited 3G areas. The other caveat here is that for whatever reason, AT&T's reliability -- particularly in densely populated areas -- has been disreputably suspect. If you're an existing AT&T user and can't seem to get a solid 3G signal on your smartphone where you're at, don't expect a LaptopConnect card to act any differently. Frankly, that goes for all carriers. Aside from T-Mobile, which just doesn't have the coverage to compete right now, you can hardly go wrong with any of these options. But as our speed tests have shown, you'd need a darn good excuse to avoid AT&T if the coverage and reliability is right.