Hi,
My music machine has W7-Pro 64bit. It's ok ... and I will leave it at that. However, the two machines that I have that got W8-Pro (32bit on both!),are smoother all around, but they also have a bigger processor (not by much).
All in all, no complaints, though I'm enjoying not having to find drivers for my butt, my teeth, my googles, my nails, my nose ... you get the idea!