I've always been partial toward serrated broadhead edges. They are much more rugged than smooth edges... rub a smooth sharp edge across a bone and watch what happens.
I've used both the Buzzcut and the Stinger and keep favoring the Buzzcut. It combines the best of both a razor edge and serrations.
As long as both are razor sharp there's not a lick of difference in my opinion. Both kill quickly, any difference in penetration is unmeasurable and put plenty of blood on the ground.
As an aside... I recommend the 4 blade. The bleeders on them are so small they make virtually no difference in penetration.