Have you upgraded to Revit 2010

Just wondering how many Revit users have upgraded to 2010?
I have read sufficient negative feedback on the ribbon, that I have decided not to upgrade.
The problem with Revit is that once a revit file is upgraded, it cannot be saved down to an earlier version. If I upgrade my software, then I have to be committed to staying on that new version. This is the first time I have not upgraded my Revit software, and I would like to get some feedback from others.
Let me know!