I totally agree with testing it on a separate system. We wiped out 2 Workspaces here (to 5.0, anyways) because we didn't know. I'm not willing to run it on my system again. We're going to try and test it on a different system the IT guys just put together.
I'm really peeved that PTC saw fit to infect modes other than dwg with the dreaded ribbon, completely hosing ALL of our mapkeys. Hopefully it's implemented better than the 5.0 rubbish........