I don't think the Berthet pedal is perfect. It holds the foot closer to the crankarm than any other pedal. This can result in too low a Q. I used to tour with Model 23's and would get shooting pains along the outside of my knees. I realized that the inside of my foot was not sitting flat on the pedal. When I changed to a wider rattrap the pains went away. I still have 23's on two bikes and they're fine for short rides, and it's nice to not have a cage pushing into my foot.
There's been a lot of low Q fanaticsm lately. Low Q is not automatically better. The appropriate Q depends on the width of the rider's hips and the natural motion of his or her joints.
Leonard Bulger
Ann Arbor, MI
(It's trying to snow.)