Far too many variables to call out a "best". Things like KE and size of game have to be figured in. For a moderate energy setup 55-60 foot pounds, pick a head that opens fast, penetrates easier and has a moderate cut..1 & 1/8" to 1 & 1/4". For higher horsepower set-ups , pick something in the 1.5 to 1.75" cut range.

IME, you cannot go wrong w/ the better quality heads from NAP (Spitfires, Scorpions, Shockwaves), WASP (Jak-hammers), and Rocket (steelheads/sidewinders). Alot of folks like the Rocky Snipers and Gators, but personally I have an aversion towards two bladed heads..fixed or mechanical.