I've been using an iPhone 4 for about a day now. Since Apple cancelled the white model, it was time to go with the black. My original iPhone was rapidly becoming a problem, so it was time.
I've owned an original iPhone, a 3GS, and now a 4. I can easily say the 4 is the best model ever. I don't need to recap why, it's been long enough that everybody knows about it.
Really, everybody. When I was at the rally on Saturday, I couldn't go 30 seconds without seeing somebody with the 4. Not just at the rally, but anywhere in D.C. They were absolutely everywhere. So many that you would think Apple was the only real phone manufacturer. I saw maybe 2 blackberries, 5 "old" phones, and 6,000 iPhones. Of all those iPhones, maybe 3 were not 4s.
One woman I talked to said she returned her 4 for to go back to her 3GS. She said she hated the 4. Good thing she was at the rally to restore sanity, because she was obviously insane!