Silver makes a simple, but great point. A weak knot (say 70%) in heavy (say 10#) material is going to be stronger than a great knot (say 100%) in light (say 5#) material. focusing on knots in the weaker material like tippet and tippet to fly knots is what's really important.

This is one of the things I like about tippet rings. Surgeon's knots are generally considered to be a little weak (I've heard 80%) and they seemed to be the most frequent point of failure for me. Tippet rings have allowed me to replace the surgeon's knots with a tippet ring and a couple improved clinch knots for a stronger system with the same tippet material.