I've had an iPhone for about three months now. I can't say anything bad about the phone. AT&T's EDGE network, however, leaves me wishing for dial-up. Thankfully, I live in a large city and WiFi's are easy to find.
I like the Safari browser because you get the real website. After years of the hideous Blackberry browser, it's a very welcomed feature for me.
The Email client is nice. I can get all my email accounts delivered to it.
The phone works very well. I love the contact's organization and the feature that shuts off the screen when its by your face.
The iPod is just as good as my other iPods. I use the iPod function of my iPhone everyday (4 days a week) at work. I used it constantly for 5-7 hours solid. I used the phone feature about 20 times a day in durations of 5 minutes to an hour at a time. Battery life is about 1/4 at the end of the day.
My ONLY gripe is you can't put your own ring tones in. You can't even use your own music as tones. Kinda lame.
All in all, I love it.