Halo: All the obvious reasons of course, but also because Halo feels incredibly over rated to me. I hate the shield system in particular, I prefer the classic health system...
You mean the dumb system that promotes running away and hiding most of the match? I hate it too.
Health regeneration is cool, but the amount of damage you can take is too much (you can be standing right next to a grenade...or get shot with an entire magazine and only lose half your shield which regenerates in 5 seconds).
CoD4 is much better >>
Also: I don't like CoD4's fanbase that much :/