How to fix AFP where some users connect after 4 minutes and others never connect (spinning progress bar and no authentication dialog)?
Yup, we saw the same exact symptoms, only on 10.7.4 machines, and after some digging, it appears to be a preference file causing this behavior.

Backup then delete the following:

 ~/Library/Preferences/.GlobalPreferences.plist


and

 ~/Library/Preferences/.GlobalPreferences.plist.lockfile


then reboot.

See the following link for more info:

http://derflounder.wordpress.com/2012/08/03/odd-afp-and-smb-connection-problem-caused-by-idisk-going-away/

If you delete the files above you'll have to redo your Mouse preferences, and perhaps something else, from scratch, but it was no biggie as far as I could tell.