I used to be skeptical of mechanicals as well. I figured that there was enough that could go wrong bow hunting without the possibility of a blade not opening. I broke down and bought a set of 125 grain rage 2 blades and haven't looked back! With the way they open there is really no chance they won't deploy and they have a chisel tip just like the old muzzys.
My concern is not them not opening but limited penetration if a shot goes wrong and hits bone.
