I own both the FIST K4 as well as the Comp-tac 2 O'clock. I have added a pic of the 2 O'Clock with a Ruger SP101.
I don't have any pic of the FIST holster but, at the outset, you must know that I am a big, big FIST fan as I have eleven of them. The Comp-tac is a much stiffer holster than the FIST, even with the thicker kydex. With my purely personal experience I have to give the edge to the 2 O'clock. Much easier off and on the belt, much more stable platform. For me, the Comp-tac is the better of the two by a long way.