Back when I started bowhunting in 1973ish, the "only" broadhead was the Bear Razorhead. The average bow weight was 45 lbs. Remember, this was before fastflight strings, carbon EFOC arrows and such. My first deer was taken in excess of 30 yards. (yes, I know better now-a-days)
When I found the buck, the point of the broahead was sticking out of the hide on the other side. The "bleeder blade" was stuck in the off side rib.
Fast forward to several years ago, I went back to the old Razorhead for my deer hunting. It appeared to me that the bloodtrails were heavier with the bleeder blades than without. The only time I had a problem with penetration was when half of a bleeder blade broke off and the other side twisted so the flat side was acting like a "snow plow". The bow used then was a 50 lb bow.
Now-a-days, after trying just about every broadhead I could afford, I still like and use a 4-blade broadhead on whitetail deer. My favorite is the Zwickey Eskimo 4-blade. Why? They fly great (even when its windy), sharpen up good, penetrate better (to me anyhow) than a 3-blade, are inexpensive (plus you don't ever have to buy replacement bleeder blades), tuff, and have the potential to put more blood on the ground than a 2 blade. I'm only shooting about 46-47 pounds (at my draw length) so pentration vs cut is always a balancing act. If I was shooting more pounds, I would be using a 4-blade Zwickey Delta. Just my experience...