I just finished updating my 2G iPhone to OS 2.0.1. Usually when I sync my phone, I skip the “backing up iPhone” stage because it takes too damn long, but tonight, I figured I’d better let it complete. That stage alone took over an hour. After the upgrade, the entire sync process took under three minutes. That’s a serious improvement. As for other changes, I haven’t had time to play with it yet. I will be sure to note any improvements or annoyances I find.