This same discussion is had every year, and what do we learn...Not a darn thing. Fixed blade shooters think they have the only tuned bow on the planet and that MH's just don't work consistantly. Same ol' same ol'.
Most lost deer are from poor shots period... If you hit the deer right, a field tip will kill it in fairly short order.
I do think fixed blades are better, but I shoot Reapers as well. I also have slick tricks that I get out on occasion. Both shoot fine, and I have not lost a deer with either. COme to think of it, I haven't lost a deer in a long while, but I have seriously restricted myself on high quality shot opportunities.
I find it unlikely that the head failed, but I can't say that as I was not there. I have seen failures on multile MH's but they did open, they just broke upon impact with bone, which is plain poor quality metal IMHO.
This argument will never end...