Well, it's been a full month since the iPhone's release, and here is as good a place as any to post my impressions...
Yes, I had activation issues. Took 12-ish hours to activate. No instant gratification for me. Since then, the only major network issue was the EDGE network going down on the first weekday after the iPhone launch (I have another entry on that.)
For ease of use, it's excellent. Better than a Palm, better than a Windows Mobile, way better than a Symbian S60 smartphone (which I swore by before this.) I have no ease of use complaints at all.
For underlying usability, lack of Flash and Java is annoying, but not a deal breaker. I haven't had a single website that I've wanted to go to that just wouldn't work. One complaint is the fact that
Stability is a well-documented problem. Safari crashes once or twice a day for me, in about 2-4 hours of Safari use per day. And early on, I discovered that if you leave the iPhone 'on' for too long, it starts to become unresponsive. (After about a week of not turning it off, I had an issue where after I slid the 'unlock slider', then typed in my code, I would need to hit the Home button for it to actually get beyond the code entry screen.)
Of course, there are some other features lacking, that are rumored to be coming soon in a software update. I figure I'll give it until Leopard comes out on the desktop to complain about the lack of those features (Notes don't sync to anything on the desktop, no MMS or AIM, etc.)
Overall, it's been great, with just a few minor nitpicks.