Muzzy's are a good blade but have a small cutting diameter. For deer I prefer a good mechanical with at least a 1 1/2" cutting diameter.
I also have a theory that mechanicals give more of a punch because of the force needed to open up, while a fixed blades goes through like butter. But thats just a theory. I have comapred mech. to the muzzy and what I have found is the mech. leave more trauma to the internals, wouldnt reccomend them for hogs though.