o.k. I'll throw my hat in the ring. I have not had much in the way of blood trails with 2 blade heads. There are several of us that are "on call" to help with tracking and dragging and the same group of us have bear/caribou hunted together. I have helped track over 20 black bears, 3 were hit with 2 blades- (none of these bears were mine.)
Bear #1 was heart shot with a 160 gr. grizzly....complete pass thru. A little hair at the site of the hit and NO BLOOD until we found the bear. Only 40 yards from site of the hit. Thick Canadian bush. 65# longbow, 700 gr. wood arrow.
Bear #2 was a double lung complete pass thru. Hair at the site of the hit, intermittent blood on the 80 yard (+/-) and a lot of blood when we found the bear. 2 blade dbl. bevel. 65# compound, 450 grain arrow.
Bear #3 was what we believed to be a single lung/liver hit. Complete pass thru. Spotty blood trail. Brought in a tracking dog. Bear was not recovered. 2 blade double bevel. 550 gr. arrow, 70# longbow.
I have killed a few deer with 2 blade heads. 3 that come to mind are- (these were all my hits)
Deer #1 8 point IL whitetail, double lung 1/4 away. Complete pass thru. Found NO BLOOD until we were within 10-15 feet of the deer. Followed scuff marks and overturned leaves for 2 hours. Deer had made it 75-80 yards. 2 blade dbl. bevel
Deer #2 mature doe broadside. Appeared to be a double lung shot, complete pass thru. Blood on arrow fletching indicated "lung blood". Minimal blood for the first 30 yards. Deer was not recovered. 2 blade single bevel. I did say "appeared to be dbl. lung". I must have only got 1 lung or we would've found the deer.
Deer #3 mature doe feeding on acorns. Broadside dbl. lung. She jumped a bit at the shot, went back to feeding and dropped over dead in a few seconds. No blood trail needed!. 2 blade dbl. bevel
The last 8 animal I have killed were all taken with 600+ grain arrows and 3 blades heads. Bows ranging from 48-55#@28" and I draw 28". All have been complete pass thrus.
6 whitetail deer, all broadside or slight 1/4 away. 5 dropped within my sight, 2 went less than 20 yards. 1 doe made it about 50 yards and then died and slid down a steep ridge another 50 yards.
2 bull caribou both died within sight. One made it 30 yards the other around 75 yards.
I guess what this means is "it depends". I do know that as I have matured as a bowhunter I am much, much more selective with my shots and I am a fanatic about sharp and I mean SHARP broadheads. If I pull an arrow from my quiver in the morning, I pull a different arrow out in the afternoon and I touch both of them up before I go back out again. That may not be necessary, but it gives me peace of mind!
I am not passing judgement on any type/brand of broadhead, just sharing what some of my experiences have been. That being said, I have pondered trying the Simmons heads from the results I have seen on this site. I have also bought 6-250 grain VPA Penetrator 2 blades to use on the upcoming VPA Hog Hunt....at least I might use them. Those Terminators have sure done a nice job for me so far!
Mike