I've used both. I used a pantin for a number of years and just recently have gone to the CMI as my climbing system has changed. I currently use an SRT ascent system that I have built on a variation of the Sherrill Frog system that incorporates a knee ascender on my left knee and is attached to a foot harness on my left foot so that both feet and the upper hand ascender are completely independent. If I used the pantin in this system, the angle between my right foot and left knee is so sharp that the rope keeps kicking out of the pantin. The cam lock and the size of the CMI does need some getting used to, but it is not that bad, I have no trouble keeping both the CMI and the left foot harness on throughout the climb. It has been a while since I tried the pantin in this system, I'll have to pull it out and give it a try again. Can't wait to see the new one though. Any idea when it will hit the market for certain?