Since I'm a two blade Stinger guy, I'll give you my reasons why. If you hit them in the lungs, it won't matter much if it's one blade or 10, the animal will usually be dead within 10-15 seconds. The four blade causes more damage and the two blade has a greater chance of being a pass through. Since they both end up being dead, I'll take the greater chance of an exit hole.

If you don't hit them in the lungs, then you have to deal with a problem, no matter what head you use. An off-hit is most often a gut shot, a shoulder hit or a spine shot. In the guts, the deer is dead with either, and both will require a long wait. With a shoulder or spine shot, your chances of adequate penetration are much greater with the two blade.

There are other little things to consider. Four blades equal more area to push the arrow off track in high wind situations. Four blades also equal greater odds of hitting a twig or deflecting off another inconspicuous object. It is also much easier to sharpen a two blade broadhead without having to purchase replacement blades.

Many consider the four blade to be a slam dunk no decision option, but they haven't convinced me.