I have always favored the four blade versions for the extra cutting surface. I always liked the way the four blade muzzy's locked together. They are very, very strong.
But the three blade versions have done well with those I hunt with.
I was in an archery only club in South Carolina and saw more deer taken with Thunderheads and Muzzy's than anything else. It is more about balancing the shaft to your bow for good flight and putting he arrow in the right spot on the animal than the number of blades.
