Is there any strength issues with the dual 80 or are they pretty equal there?
Dual 80 is considerably stronger from what I have seen. The 936s and Williams are strong, high-quality ratchets, but the Dual 80s do not give them anything. The Dual 80 design is stronger, smoother, and has less swing arc. It beats the 936 in every category of ratchet performance. Their is a reason Snap-On does not sell the 936 anymore, given the choice no one would decide to get a new 936 over a new Dual 80. The Williams is a steal for the pro e though, bot saying its not good, just that the Dual 80 is better.
This makes sense when you consider the pawl design. The teeth are smaller but there are more engaged and therefore you have a stronger mechanism. Think about a Ford 9", the 31 spline axle is stronger than the 28 spline axle because there are more splines to hold the power.