For me, the big draw was knowing I could get all the benefits of a fitness app in a small package without worrying about the battery. When I'm 30 or 40 miles from home, the last thing I want is to be stranded without a phone should I need to call my wife to pick me up or, worse, if I'm in an accident. By leaving my phone running with the screen on, pulling data from sensors and recording via GPS, I knew I'd eventually be out riding and need to use my phone, only to pull it out of my pocket to find it in the red. The first longer ride I did with the Garmin was a joy simply because I didn't have to worry about the longevity of the Edge 510. In general, the battery is pretty darn good. During a charity ride a few months ago the device lasted just over seven hours -- something my phone would have not been able to pull off.
The addition of a color LCD display on the 510 is a big step up from the previous generation Edge 500. This seems rather trivial, but the Edge 510 is capable of giving you turn-by-turn directions. All that color is helpful, too; it's less of a struggle to make out directions now that roads and arrows aren't rendered in monochrome. Now, don't get too excited about seeing turn-by-turn directions. It's nothing more than an audible tone to alert you of an upcoming turn with an arrow pointing on a small section of a map. That's it. If you want more detailed GPS data then you have to go up to the more expensive Edge 810 or Edge 1000 which allow you to download more robust maps.
Perhaps the best feature of the Edge 510 is one that doesn't even benefit me specifically. You see, as great as cycling is for your health, it can also be pretty dangerous. My wife used to worry when I was riding solo, but now she doesn't, thanks to a feature called LiveTrack. Before I head out, I simply enable LiveTrack and she gets an email with a link to follow me on a map. There's no more worrying -- she can just can open the map to make sure the little dot (me) is still moving along. And to my surprise, this isn't too much of a burden on either device's battery. I've been able to use LiveTrack for close to three hours before seeing a battery warning for either my phone or the Edge 510.
I must admit, I do have one issue: the touchscreen display. At times when I'm trying to navigate around, I feel as if I'm using a cellphone from 2007. Moving through pages can be frustrating, often requiring me to swipe from off the screen or else it doesn't register the action at all. Sure, I can just leave it on one page, but Garmin lets me have up to five and I like to have ones set up for different workouts. And let me tell you, when I'm riding up a 7 percent grade hill, having to fight with an unresponsive screen is the last thing I want to worry about. In colder months I don't even bother with the display -- it's even less responsive when I'm wearing full-finger gloves. I recognize the Edge 510 is the company's lower-end cycling device, and I have adapted to its temperamental nature, but I just wish something costing me $300-plus offered a better touchscreen.
As much as I like the Edge 510, it's probably overkill for a lot of riders. I personally like having my cadence and heart rate synced into Strava, but not everyone may care about that. In those cases, sticking with a traditional bike computer and just using your phone will work fine. If you are of the data recording group but find the $330 price point to be too high, you can probably snag the discontinued Edge 500 on a good deal. You won't get LiveTrack or a color touchscreen, but you could also save over $100.