Just to start off with, I installed this and then soft-reset before carrier customization could run. So you can't blame for my issues.
I haven't used my phone too heavily, but here's what I've found:
1. The record button "press" and "hold" configuration seems to be swapped. Hitting it brought up notes even after I specifically configured it to do nothing on that. Removing the "hold" notes functionality fixed it.
2. WiFi seems shaky, as others have mentioned. I was able to connect to my WPA-protected AP, but only about half the time.
3. ActiveSync sometimes gets "stuck" even after you pull out the cord. I can't replicate this consistently, though.