Originally Posted by Quentin2
The only negative I've seen is with lots of flipping up and down the detent can wear to the point where the sight won't stay down. Don't cinch it down real tight or you can snap the mounting screw.
The friction point wear is seen on the off-shore copies of the Ma-tech, the GI models are more robust. The attaching screw is a known problem, BAD makes a improved attaching screw and clamp, great $5 upgrade for the Ma-tech.
I've had a ma-tech on my M4gery for 8-9 years now and it gets the job done. I do agree about a larger aperture for low light shooting.
Two other sights for the OP to look at are the LMT A2 style clamp-on and Troy. Both are very well built.