Here's one of many discussions on the crossfit boards concerning the dead hang vs. kipping debate. Personally next time I do a ladder I will probably just do deadhang so it is not my skin blistering that limits me.
The thread begins because the video posted that day was of a guy doing max dead hang pullups to failure as quickly as possible, then resting and doing the same number kipping - he was able to do them about twice as fast so his "power" output doubled. The OP took issue.
kipping v. deadhang