I like PCs better, because I'm more familiar with them plus they can run a better variety of programs in general. All the computers at my school are Windows-based PCs and I've been using them for ~7 years at this school and 2 in my last school, plus my family has always used Windows-based PCs, so I'm a lot more familiar with PCs than Macs. A lot of the things I get are .exe files, and from what I know, these don't work on Macs.
IMO, I think that Macs sometimes have the ability to be faster, but there just aren't enough games and compatible programs for them. It's bad enough with 64-bit Windows trying to find stuff that works. Agree or disagree, I don't care. Just my opinion.