Installed Beta 2. Seems to have fixed the lock button on the Start screen for me, and also defaults Notifications (e-mail/MMS/etc) to not use vibrate by default
I don't know if this is new or I just didn't notice it before, but if you press and hold the START button you get a cool little HTC "Showcase" thing that comes up. It doesn't seem to work under
all circumstances, but when it does it's basically an enhanced version of the old X menu from 6.5. Nice. Much easier than installing a custom task manager.
edit: The volume control is fine, I had installed a bad taskbar update. My fault, apologies. I need to modify the one I have that works to have nicer e-mail/SMS/MMS icons