Happy.
Sound quality is good, speed is good, and considering this was the primary reason for my upgrading, I'm convinced it's well worth it. In many cases I no longer see much of a difference between my being on WiFi or 3G.
Battery life has not been bad for me either. Maybe I lucked out. I don't know.
Oh, one tip that I noticed has not been said at all: if you're in a 3G fringe area, or in an area with no 3G at all, then you REALLY need to turn 3G off. In both cases, the iPhone will be operating both radios (3G and GSM), as it will actively keep trying to find and lock onto a 3G signal. This will kill your battery life even more than just having 3G on all the time in a good signal area.
This was a tip I learned waaay back when I had a BlackJack and a Treo 750. Regardless of what phone you have, they're all set to favor 3G when possible, and unless you turn that off, they will thrash your battery hard looking for that signal if they can't find it.