Does anyone have the iPhone 3GS, 4, or 4S with one of the new regional carriers that are offering it now in the US? I have seen videos of the C-Spire one on YouTube but none of the ones from the GSM based regionals like GCI in Alaska. How does it compare to the ones for AT&T, VZW or Sprint? Can you still walk into an Apple store for support? I've noticed that Apple does not sell these in the Apple store, so it looks like its carrier store only for these devices.