Got both, the Win Indexes are about the same on my MBA 2012 (11", i7, 8GB, 256 SSD), Mountain Lion, Windows 7 Ultimate 64-bit:
Win Index (CPU/RAM/UI/Game/HD)
//s7 4,7/5,5/5,5/2,0/7,5 (my old //s)
//s8 5,5/5,5/5,5/4,8/7,9 (upgraded to...)
VM5 5,4/5,5/5,9/4,9/7,8 (trial version)
Decided to continue on Parallels, for no other reason than being used to it...
Win Index (CPU/RAM/UI/Game/HD)
//s7 4,7/5,5/5,5/2,0/7,5 (my old //s)
//s8 5,5/5,5/5,5/4,8/7,9 (upgraded to...)
VM5 5,4/5,5/5,9/4,9/7,8 (trial version)
Decided to continue on Parallels, for no other reason than being used to it...