Overall it's a great piece.. it doesn't change the grip, is pretty interchangeable between glocks, etc. It's pretty much perfect aside from these 3 gripes:
1: You have to squeeze hard-ish to activate the laser. Not a big deal as you should be squeezing anyway, not overly hard but harder than I expected.
2: Sometimes my finger will slide along the bottom of the trigger guard (but still inside of it of course) and the housing of the laser - it's a bit uncomfortable.
3: Limited holster selection. There are a few. I had no issue with an IWB holster but I also wanted a holster for training courses/etc - I am looking for a pancake style OWB an cannot find anything I like.
This review was written in the old system and had content requirements that are different than reviews written today.