I have already pre-ordered mine from radioshack. I am going to try it for 30 days and see hot it goes. I haven't canceled my iPhone ATT plan. I am going to have two phone numbers for at least 30 days.
As of now I know a few downsides for this phone (from reviews, other users):
1. Battery life is terrible
2. HD Video recording is really not so good(even compared with 3GS)!
3. No data/voice at the same time. (Don't tell me it's not the phone but the network etc. Whatever it is it's a problem for me at least.) I know sprint is going to try to implement it but I heard it's only possible for wimax. Anyway I am not going to have wimax in LA, at least for now.
I will have my own review once I get it. If I decided to return it, I will let you know what really did not work out for me......