I love windows 8 never felt windows 7 was anything other than a new vista.
However i used windows xp last summer on my old work laptop "car diagnostics" and mapping Standalone ECUs.
I kind of wished that XP was dead because 4 days with that crap and the unstability told me that windows have only improved over the years.
Anyways before i upgraded to windows 8 on that laptop i reinstalled a fresh version of XP and i am sure that win8 is faster on that computer. (panasonic TB CF-74).
Never looked back and never will..