We have been having trouble pushing 2010 out to users via Active Directory, and have been working with our VAR to try to resolve them. One thing that didn't seem obvious is that you need to push it out to computers, not to users.
More interestingly, they sent along what appears to be a work-in-progress document with updated information and tips for using AD. This stuff seemed quite good and very helpful. Hopefully they'll get it integrated in the documentation soon, but maybe someone else can learn from it in the meantime.