I have the Blade-tech IWB, for my mid-frame Glocks. I have carried a 23 in it extensively, and a 35 in it occassionally. I love it. It is my most common CCW holster, for at least the last months. Prior to that, I was doing a lot of mexican carry when I couldn't carry on the belt... I have never liked the thick IWB leather holsters, now I don't have to worry about them anymore.
I also recently got the same IWB (with straps and snaps, not J hooks) for my Full size USP .45. I would never have dreamed that there would be an IWB holster thin enough for a scrawny guy like me to carry it comfortably, but I have carried the USP for several hours at a time, just to try it out, and it is incredibly tolerable.
I now have 4 Blade Tech Holsters, my wife has one, and I have a cuff case, flashlight holder and several magazine holders from them as well.
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-Essayons