I've been using it a few days now. My only problem was with some false positives, raised red then lowered green and blue by 10. I haven't had a negligent discharge since.
Really it doesn't give a huge advantage with most weapons, assuming you're using a rapidfire for the semi-autos and have some skill. However it really shines with the HVR, aim at a corner and it'll take the shot before you even see the enemy pop out, or just scan back and forth under a car to easily nail the feet of enemies taking cover.