I feel it really depneds on several things. First what material we are talking about, the type of bow and arrow setup, and the specific broadheads. In bone the chisel tips to better when shooting moderate to heavy equipment. In hide the two blade cut on contacts do better, the three blade cut on contacts are about half way between. The two blade cut on contacts with bleeders do well until the bleeders hit, then they slow down some. In animals two blade heads have the potential to penetrate better out of the same setups. One reason is that they do slip through the hide easier, then 2nd is that they can slip between ribs, where a multi-blade head can' t. If a two blade goes between the ribs you will gain more penetration into vital tissue right off the bat. combine that with the cut through hide easier and you get better penetration. In my testing I have found little differnce in penetration between the two styles, but my tests are not animals. Bottom line smaller = better penetration, the fewer blades or the smaller the total cutting surface the better your penetration. For most setups I think it' s moot point, not worth the worry. for low Ke setups like those used by women and young hunters or for traditional shooters, I think the two blade cut on contact heads gives them the potential to get better penetration, and with these setups you need every edge you can get.