Originally Posted by cyccommute

I think what most people miss on that video is the bit at the end (around 7:15). The test they ran was one test at a steady state. Simon states that he's not going to give up his clipless because he does pull up on the pedals during hard efforts. This is something that I have noticed as well. Even on a touring bike, there are times when I have to pull up on the pedals to get a little more boost. Out of saddle efforts if nothing other than to stretch out muscles is much easier if your feet are attached to the pedals.

Off-road, clipless offer more security because your feet are attached to the pedals and are less likely to slip off. Additionally, as Simon said in the video, it's much easier to bunny hop while clipped in. Even if you are just lofting the rear wheel over a rock, clipless makes it much, much easier.