I have had no problems with my iPhone. Just the rare spot where there was no coverage while driving. I even had coverage in the mountains. Only 1 dropped call that I recall in 2 years. Never a problem with the internet, email, etc.
The only thing I don't like is that Apple and Adobe aren't working together. Oh, and gmail stinks if you need to search it - it was rare for it to find anything.
If you do get it, get the 32GB...I can only fit 5 apps on my 16GB because I have a lot of podcasts and music.