I just updated my Vista64 PC running Ensemble3 with Windows7 RC1 and after doing some test I can say it seems to work really well, the system feels much more responsible than with vista. With vista I always had trouble with the network connection, windows7 solved it for me. The update procedure was smooth, I only had to update the eLicencer software. Everything else worked instantly. I read that from now on microsoft recommends anyone to switching to Windows7 RC1 instead of vista.
Of course I duplicated the vista partition before the update so I could go back in case of trouble.