I’ve upgraded our Exchange 2007 setup to Exchange 2010 and two irksome issues cropped up that sponged up a great deal of my time:

• First, when I was moving users (aka ‘local move’) in a remote domain from the Exchange 2007 server to the Exchange 2010 server I was receiving the ‘insuff_access_rights’ error and I was unable to move the mailbox*.  Eventually I did have to do the ’include inheritable permissions’ checkbox on most of the users, but since that didn’t work right away I investigated quite a bit more before finding that the permissions for various ‘Exchange’ entries at the root of the remote domain within active directory users and computers were “goofed”.  Things went more smoothly after setting the matching entries to (about) the same permissions as the ones at the host domain.
• I couldn’t uninstall Exchange 2007 since it was hosting unremovable folders on the public folder database (‘Internet Newsgroups’, etc.).  I tried to do things the right way, but wound up resorting to the ADSI edit tip here.

*By the way, I liked the ‘cached move’ method in Exchange 2010, but why can I clear out the flags for successful moves in the GUI, but I have to resort to a painful command line method if it fails? (Which, it failed for me a lot while working on it).