I waited for the opportunity to get one of these holster for quite a long time and was finally able to do so this christmas. My eager anticipation was quickly replaced by total disappointment. The holster body itself is well designed and well thought out. It was easily adjusted between my G21 and my G23, with or without an X300.
Where this holster fails is the harness system. It provides absolutely no solid support for the weapon. The elastic is skinny and weak and design causes failure of the system right out of the box. By design, the weight of the gun is pushed out in front of the harness by virtue of the horizontal carry position. This causes the leather harnes to rotate forward and the gun to carry at about a 45 degree angle, no matter how you adjust the hangers on the leather harness. The wimpy elastic straps are a joke and provide absolutely no support to the harness and holster body at all. Within about 5 minutes of putting this rig on you just end up with a sagging, drooping, uncomfortable mess. A thorough disappointment for me. Made it to the "holster box" faster than any other holster I've ever purchased. No wonder I never heard much about this one.
Pros: Holster body design. Fits multiple guns, easy to use with one hand. Quick on the draw, easy to re-holster. Secure. Concealable.
Cons: Really poor harness.
This review was written in the old system and had content requirements that are different than reviews written today.