I always thought the CompTac's were built "backwards". The leather should be on the outside, so the kydex can block the sweat from soaking through and causing problems. Wet leather is miserable, and even more so against bare skin and youre active. It just rubs you raw and to add insult to injury, the chemicals in many leather holsters, just aggravate the problem even more.
Kydex on the other hand, is 100% water/sweat proof, slips smoothly across wet skin like it was lubricated, and there are no chemicals to aggravate you even more.