One word review: Awesome
Okay, a few more words:I also had a 3G, so I was ready. The iOS4 software gave me some nice features on the 3g, but some things stopped working because its poor processor is simply overtaxed. iOS4 was designed for the iPhone 4 and works great on it.
iPhone4 is way fast. iPad fast. My 3G, even before the iOS4 update was really doggy. I now have a phone that works for me and doesn't make me wait for it.
The screen is way beautiful. If you haven't seen one in person, you have no idea how great a handheld screen can be. Tiny print is visible. Pixels are non-existant. They're there, but you cannot see them, unless you have better eyes than I have.
The camera. Ah, the camera! It alone would make it worth the price. It takes better pictures most of the time than my $400+ 15megapixel Canon G10! I don't even think about using that thing any more. Low-light shooting is a delight. In that sense it is WAY better than the G10. It probably goes without saying that it absolutely destroys the camera in my 3G. Good thing I got the 32Gig model because I'm going to fill it up with pictures. (See previous post.)
I haven't tried FaceTime yet--nobody else in my family has a 4 yet, and I haven't gotten around to calling Apple.
It's nice to have video. 3GS owners already know that, but it's new to me and I haven't given it much of a workout yet. The upgrade here is that it's HD (720p) as opposed to the 3GS's standard def video. I got the iMovie app, but haven't done anything with it yet.
A note about the antenna issue that is in the news a lot lately: Yes, I've experienced it. Many have reported that their reception actually improved with the iP4, so it may depend on a lot of factors that don't apply to everyone. One interesting factoid is that SOME 3GS users have been affected by this problem as well. One rumor I read this morning is that the problem may arise from the way the software picks cell towers and that there may be an iOS4.01 update out this week to address the issue.
Overall, though, it's a great phone.
My favorite feature? It looks incredible!