With that in mind, you're still going to have to ration data compared to how you use it back at home. Also, be sure not to run over -- It costs $50 for each extra gigabyte you need. Calls to any country cost 35 cents per minute.
How does it compare to other carriers? It depends on what you need. Verizon isn't exactly generous with monthly international data: you're only paying $25 per month outside of North America, but that gets you just 100MB with overages of $25 for every additional 100MB block. You're better off paying for a day pass, then. T-Mobile offers unlimited free data out of the gate, but only at 128Kbps; you'll need a One Plus plan to move to a still-paltry 256Kbps, and LTE speeds are only available in Canada and Mexico. Sprint also takes the free-but-slow approach outside of North America unless you pay for a pass, although you can spring for weekly passes (usually $25 per week) that represent better bargains.
In short, AT&T's newer Passport packs make the most sense if you have an extended stay, want fast data and want to keep your own phone number. Otherwise, you may want to opt for day passes, another carrier or (if you have an unlocked phone) a service that offers local data where you're traveling.