I has been two days now of iPhone 4 use. I was able to upgrade from iPhone 3G to the 4, so the experience improvements over the past two years are rather large.
I try to use Safari on my phone for a few items. One of those items is my fantasy baseball page. On the 3G, this was a 40-50 second load on Wi-Fi. With my new phone, it is 8-10 second load. I am actually able to make roster changes and view my matchup scores in the time it would take to only view my roster. Great improvement on surfing.
I have not done too much with the multitasking, but that does appear to work very well.
The video has been a lot of fun. Just took a few sample videos of my son and loved the outcome. The camera is leaps and bounds better than before. How is it leaps and bounds? I can actually get the phone out of my pocket, unlock it, open the camera application and take a picture all before my old phone would even open the camera application from a non-locked state.
I have not had the antenna, but I try to use headphones whenever possible.
I will be getting a case. Not because I don’t think the phone is weak or fragile, but like every other iPhone, it is hard to handle without some sort of grip or texture to cling to.
All in all, pretty pleased I have the phone. Anything is going to be great when you wait 2 years to upgrade.