All I can say is WOW WOW WOW!  I am very impressed and very stoked!  I have successfully completed one dual server install and upgraded a very active, multi-project single server installation.  Each took about 3 or 4 hours, where most of the time sucked up backing up and copying db files and ISO images around.  Huge improvement over the past installs.  This product just gets better with each release!  While the release candidate brings a number of improvements, a few of my favorite are:

• Removing the BuiltIn/Administrators group from TFS groups the users contained in that group actually disappear in the drop down lists
• Real user names in drop down boxes rather than aliases
• An upgrade procedure.  B3 to RC was very straight forward and easy
• Huge performance improvements
• New reports
• "Go To Changeset" ctrl + g in source control
• Installation and health checking greatly improved
• Installation instructions are greatly improved

If your one of those developers who reads blogs rather than instructions there are a few things to note:

• Reporting services changes, dual server, uninstall/install or install
  • Reporting services was moved from the data tier to the application tier
  • Uninstall Reporting services on the data tier and delete its two supporting databases
  • When you install Reporting services on the application tier you cannot run the service as local system.
  • That user you've selected to run reporting services will need "Log On Locally" rights on the appropriate machines
• The TFS upgrade utility can be found here: Upgrade Utility
• There are two hotfixes which have to be installed on the appropriate machines, both are found on the media. KB913393, KB912838
• Use the server name rather than the IP for the TFS data tier address
• Run TfsBuildUpgrade.exe from a client machine and not the TFS server
• For an upgrade, backup those databases
• Just read those instructions!

Hats off to the product group, for a job well done!