Test it - of course. :)
We found the transition to be a bit more smooth when restoring a backup of 8.72 than trying to perform an inline migration. We also changed our organizational schema (from departments primarily to about 10 "Sites"), so there was a lot of work parsing out the computer groups, managed prefs, mobile groups, etc. Also, we are still fiddling with the permissions for Casper access which demonstrate some odd behaviors when used in conjunction with sites. Basically, we think you are better off creating permission sets for each site than attempting to have a single user join an access level, than a group dedicated to a site, or one user being an administrator for multiple sites.
