For the right purpose, this is perfect - Sightmark Sure Shot Reflex Sight

If you want a sight for rimfire plinking, I am convinced that this is the single best red dot on the market, for price, fast target aquisition, reticle choices, brightness, cheap batteries, light weight, etc. I am extremely happy with mine and have fired hundreds (if not thousands) of rounds through my M&P 15-22 using this sight. It has held up for 2 years and is as good as new.

What this sight is not:
-Military grade, for wet, cold, hot, sandy, etc. conditions. You can't go cheap when it comes to that. Get an Aimpoint or an EO Tech. This is not a cheap EO Tech. The Bushnell Holosight is a cheap EO Tech. This is a plinking sight.
-A centerfire rifle optic. I know, it was in Call of Duty and it looks totally awesome. CoD isn't real. Don't expect this to hold zero and take the abuse of centerfire shooting. I will be honest with you; I have not tried. It may work. But please don't bet your life on a $50 optic. At least get a Vortex. They're cheap.
-An airsoft sight. You might get away with it. I used to play on a serious outdoor team, and I can tell you first hand that I would not be putting this type of optic on anything I was going to depend on. I'm not glorifying airsoft, but you tend to beat up your gear more than you do at the range. I doubt this would take a solid knock against a rock or a BB to the glass. Just being honest. Knock-off Aimpoints are just as cheap and I would expect more durability out of them.

As long as you are getting this for what it was made for (plinking on a .22), it will be the best $50.00 you ever spent. If you plan to bring it into combat, you're wasting $50.00 and possibly your life. There is no such thing as a $50.00 combat optic. Vortex makes good near-combat grade optics for about $150-250.
Pros: Crisp image, fast and fun to use
Cons: None

This review was written in the old system and had content requirements that are different than reviews written today.