i'm doing the same but will have to wait till feb for a full upgrade. i can't decide between the sensation or the galaxy s2..
You know TMO might not get the GS2 so are you planning to switch carries. I hate the thought of switching AT&T. Good thing about the Sensation it has AT&T bands so if the merger happens I guess those who get the phone will still be able to get 3G on AT&T.