Welcome to the all-new Windows Central Forums! - We're still moving some things around, so you may see a few quirks here and there, but we're working on getting things fully completed as soon as possible. For now, take a look around, and if you run into any major issues, please let us know in this thread!
Yes.So you're saying we could hypothetically use a AT&T Lumia 900 on T-Mobile at the end of the year and get 3G / HSPDA+?
While I highly doubt they will have every tower in the entire country switched over by the beginning of next year, it should be a large majority of their markets - of course, they're focusing on big cities first and working out from there.
This is from May, but it shows that T-Mobile will be confident enough to try and pull in iPhone users by the end of the year:
T-Mobile CTO Says Network Will Be ?Should Be Ready? For iPhone Users By Fourth Quarter | | TmoNewsTmoNews
I'm confident enough in this to be betting on buying a 920 unlocked (unless someone comes out and surprises me with a 3.7" WP8 device or Lumia 800 clone before then), since I'm with T-Mobile myself.
Yes.