So pretty much kickboxing (shiny pants) vs Muay Thai?
Like HighestHand said, if they're similar skilled, and around A-class+ type fighters, I would give it to the MT guy. Clinch fighting, sweeps, and leg kicks as well. TKD + Boxing usually means a bladed stance of some sort, and that leg is just asking to get chopped.
Leg catch -> sweep or clinch tosses -> ground work / gnp