The CLAW rear sight was designed to aid in one handed manipulations and it does just that. I've had it on my Glock 19 for a while and here's what I've found.
-It really grabs onto hard surfaces to aid in one handed racking of the slide
-Standard heights for Glock (large and small frame), and M&P pistols
-Black nitrided finish for durability and hardness
-Cost. It's only $24 for the rear sight. Tough to beat that.
-I'd like to see serrations on the rear of the sight but that would likely add cost. It's a trade off I suppose.
Here's a video with some shooting, close up shots of the sight on the gun, and my overall thoughts one the sight: