Read more carefully and the FAQ on T-Mobile's website. T-Mobile's FREE international data roaming is limited to 128Kbps. That's SUB EDGE speeds. Hey it's free but if you can live with that then you're fine. It's enough for text/email and maps. Forget about video and any multimedia. T-Mobile, like Verizon lets you purchase data packs to enable full speed roaming on HSPA+ networks worldwide (LTE roaming is not enabled yet) with T-Mobile being the value leader in the costs ($50 gets you 500MB of FULL SPEED data roaming for 2 weeks, that's more than 2x the amount you get on VZW. AT&T's costs are in the middle.)

T-Mobile's TRUE innovation is unlimited text messages while roaming internationally and 0.20/minute in the same 100+ countries.

I know people who will get a T-Mobile plan just for the cheap international services (calls and text, occasional data) and they use Verizon/AT&T domestically.