I'll get straight to the point. The iPhone 2.0 sofware is great in many ways, but it has also made me miserable! The interface is stupidly slow and sometimes unresponsive for moments at a time. Everything accessing the preferences, camera, and serveral applications from the App Store freeze a lot, and at times cause the phone itself to reset.
Syncing and backing up takes forever, even when the phone is just over half full with audio/photos/videos. I recently restored my phone again and so far things have been more stable, but some of the menus and applications are slow. I hope this is something that gets fixed in an update very soon.
The App Store is great and all, but more and more just barely seem to work properly. I hope this is the fault of the 3rd party developers and gets fixed up in a timely manner. I love the App Store, but these negative aspects just take all the joy away.