Surgeons knot failures
I go back & forth between the surgeons & blood knots for leaders. What I've found is that I don't tie blood knots that are worth a darn in the field. But if I use a triple surgeons knot, i.e 3 turns of line around the finger, in the field it gives good strength. At home tying up leaders I prefer the blood knot because they seem to lay out straighter.
I find that both are dependent on good tightning technique. The blood knot seems to sensitive to the speed you tighten it at, while the surgeons knot is sensitive to pulling all 4 strands of line simultaneously.
If I had to choose only one the surgeons would get the nod.
At the fly I'm an improved clinch person, but am evaluating others.