Jay,
I believe that the manufacturers will be tweeking the bonded bullet performance for the next while. One important performance factor is how quickly the bullet begins to open up and how soon it gets to full "mushroom". In my past shooting we have seen bullets start the wound cavity after only three inches of penetration, others drilled in 9-10 inches before the wound cavity really started (this is in identical medium). I assume the initiation of the wound cavity is when mushrooming really starts to happen - admit that I am not a ballistician or engineer. No doubt some guys here have real knowledge on what is happening.
I am going to shoot all the bullets into a uniform medium and recover the bullets to compare how they did. Will do this at 200 yards, then will do it out longer. Hope to do it at two muzzle velocity levels, 2600-2700 fps and 3100-3200 fps. Will measure muzzle and impact velocities simultaneously using two Oehler 35P's.
The manufacturers are adding bullets at a fairly steady rate, makes for more work. One deadline is May 15. Going to do some bullet testing in Texas on wild hogs also before that date.