This is a good thread. The best I have used is the Muzzy. I have had countless kills with the small 4 blade 90 grain heads. Last year I tried the Simmons Land Sharks in 125 Grain. They are a 2 blade head very similar to the Simmons pictured on page one of this thread, just smaller.
I had 2 kills with them, a small doe which ran a good ways with no blood trail at all. She was hit through one lung and the liver. I could not track her by blood. I ended up searching for a couple hours after dark in a field with high grass looking for signs, no blood anywhere. I just told myself she was hit fairly well and guesses how far she could have traveled and began to walk circles in the field (golden rod waist high). I found her after about 45 minutes. That was experience #1, not the best.
#2, a couple days later passed through an 8-point at close range, steep angle. Again caught one lung. He ran off about 70 yards into the edge of an open field and stood in one place for about 5 minutes, not moving a muscle. I had glasses on him and could not see blood. He finally decided to start moving again, he turned, took about 3 steps and began to stumble like he was drunk. He gained is legs and moved down the edge of the field out of sight. I gave him some good time, tried to follow a blood trail, but not much to be found. I found him just over a barbed wire fence dead, jumping it must have been too much for him.
I was disappointed with the performance of this head. Granted both were just a single lung hit, but no blood at all to speak of. If it were not for my knowledge of the area the doe would have rotted. I wanted a good 2 blade that I could resharpen each year and use over and over. They fly good, a better double lung hit would provide better results for sure, but I may slide back to the muzzy once again. They bleed good after a similar muzzy hit. I could also try adding in the small bleeder blades to the Simmons, but they do not lock into place (a disadvantage - I'm afraid of arrow drift).
I just think the hit has to be more precise with the Simmons to get a good blood trail. The single 2 blade design does not leave a large enough entry/exit wound from my experience to date.