I just put Windows Vista Business on my laptop as the HDD died. EFILive 7.3.3 installed without a problem.
Only thing is the first time you open it you have to choose to run both Tune and Scan Tools because the programs are not signed. A tick of a button and you never see it again though.
The one bug i did find is that the new Aero interface Windows-Tab key combo doesn't show a preview of the Scan or Tune tools all the time. It shows the sheel with the program logo but no the actual MAP or table that I'm viewing.
Installed the drivers, warns you if you really want to install them, but it installed just fine and did a few hours of logging tonight without a hitch. All the maps, charts, PIDS, F3, F4... key combos all still work, as with the Tune tool