Over the last week I have spent the time to upgrade the existing Windows 2008 infrastructure to Windows 2008R2 SP1. I had been running 2008R2 on a couple of systems, but decided it was time to refresh the environment. The upgrade process worked like a charm, and all of the systems updated correctly. The database server was in sad shape (it was a VM that was over 3 years old), so it was time to reinstall the OS. Fortunately, MySQL 5.5 works just fine on 2008R2.
As for patching, I managed to also patch the systems to 2008R2 SP1 without any issues. Exchange 2010 and the AD systems took the updates just fine. 2008R2 has proven to run a little better and faster under vSphere 4.1U1. Even the WDDM video driver works perfectly fine!
In combination with Windows 7, the file transfers are very fast. All in all worth the time to upgrade.