Christian Thibaudeau is a huge supporter of the Behind the Neck Press, so I figure this would be the best place to discuss this particular movement.
Is it optimal to do high rep sets of the BTN Press? By high rep, I'm talking about the 8-10 rep range. I've run across a couple programs that use the movement in the 5 rep range. However, I plan on using this particular movement as assistance work for my Push Press, and I usually tend to do 3-5x10 for my assistance exercises.