Hi
well Forget about the 2G speed for now, do you have unlimited data with AT&T? probably not!!!
what will happen if you hit your data limit with AT&T? they will let you enjoy the data, then cry when you get the bill
or simply block your usage till the next bill cycle.?
What T-Mobile does is that once you hit your data limit they throttle the speed to 2G speed, yes it is so SLOW
but still you can do things with no extra charge. so if someone has 1,2 or 3 GB of data and used them he/she is supposed to be done with data usage no more!!!!! so if T-Mobile still allows us to use their data but at a slower speed, do we need to act bossy because we can't use it the normal way streaming and playing games etc... ????/
Now if you're switching to T-Mobile and you live in a 2 G area now that is different, and you should know what kind of service are you gonna get where you live, it would be a good idea if you take the one week test drive before you switch.
Nobody can specify a speed since it's not constant, if your phone says 4GLTE yes it's fast but you don't get the same speed all the time nor everywhere, lots of factors play a role in it, the same applies to 4G, 3G and 2G
now regarding the international roaming, yes it is supposed to be 2G speed but hey you might travel somewhere where they don't have 2G to start with so you will get what they have, it could be 3G or 4G or whatever, my spouse was in Ecuador last month and it was a 3G service that wasn't bad at all.