Well, please let me toss in my experience for what it's worth...
I'm in charge of making the user-builds for a large marketing agency - so when a new OS drops it's my ball to catch...we have mostly Macs on the employee desks and a windows server network.
I performed a clean install of Mountain Lion 10.8 on a 2.53Ghz i5 MBP with 4gb RAM
I was able to create the local admin account just fine - I was able to bind the machine to the local domain just fine with my own AD account - I was able to create my own mobile AD account on the machine just fine (the first time).
Problems started occurring when I logged out (of the mobile AD account) and needed to log back in - the login screen shook it off as if I had mistyped my password - I had the same results after more careful attempts - I could log back into the local (non-AD) administrator's account.
• Checking under the "FAST USER SWITCHING" menu, I wasn't able to see my account
• Checking in Active Directory, my account was locked out.
• Checking in the Directory Utility, I was able to see the AD details - I was even able to use my credentials to authenticate there
• Initially unlocking my account allowed me back in - only to be locked out again next time I logged out and wanted back in. (sometimes AD will show my account is actually "locked" sometimes it doesn't
• I had read that it could be connected to the Group ID - changing that didn't fix anything for me.
• I had read that once an account was working it would continue working - not in my experience - I've been continuously testing with my AD account - sometimes it works, sometimes it doesn't
• Regardless of what error messages I've gotten, I've come to realize that resetting my AD password does nothing - only unlocking in AD or waiting for it to unlock itself over time (supposed to auto-unlock after 15 minutes, but I've noticed it does it sooner - like within 5 minutes)
• I've tried to delete the mobile user account and re-create it - even going as far as unbinding and rebinding the machine and the issue still persists.
• Currently, I'm in my mobile account and it behaving - I can authenticate to install software and and unlock the screensaver without issue - but I know if I were to log out and attempt to log back in, it would shake it off and I'd have to wait for about 10 minutes before I could get in, but usually that would work.
So I'm now cautiously installing some software and building a user account that I *may* eventually be permanently locked out of...only time will tell...
• Please ask me any questions, offer up suggestions and I'll do what I can to help puzzle this one out...
Thanks,
Vann