The technical answer to your question is basically simple. Most would agree that all things being equal, a two blade will penetrate better than a three blade, and a three blade will penetrate better than a four blade etc. So if penetration is a concern I would recomend a quality two blade head. There are a number of good ones. In no particular order; Bear, G5's B52, Magnus, and Zwicky to name a few.

I like a three blade for psychological purposes.<img src=icon_smile_shock.gif border=0 align=middle> Theoretically at least, on a three blade one blade will be cutting against the grain of the muscle and therefore the wound should be harder to plug up, yielding a better blood trail. All of that is debatable. Nevertheless I have had good results on elk with the following heads, again in no particular order; G5's Montec, Muzzy, Rocky Mountain Titanium. I have never used a Steel Force on an elk but have good friends that have and they have performed very impressively.

Of course there are others that will perform well too. These are just some I have personal experience with.