People who whine about Exchange 2010 SP1 not being "stable", "buggered" or whatever should conisder the complixty of the product, and the hundreds of thousands of lines of code this involves. Just upgraded different environments without any issue, including a test lab from SP1 Beta to SP1 RTM.
The devteam *can not* test each SP/rollup on *all* possible environments; of course they're testing them, but the core assumption is that the environment to upgrade is mastered and clean.
Anyway, dear DevTeam, there's no (public) mention on the move of the following settings:
- Address Book throttling moved to the Throttling Framework (companies with BES will be interested in knowing ;))
- OWA/IM integration: configuration during upgrade will be cleaned up (removed from the Web.config) and will have to be reconfigured with the Set-OwaVirtualDirectory cmdlet.