I've used one of these and it's not near the quality of the Bushnell or Eotech sights, but it will hold zero and do the job. The biggest problem I have is that it slightly magnifies and displaces the target so that when I keep both eyes open, I see two targets, one slightly above the other at ranges over about 50 yards. As long as I keep one eye closed it works great, but that kind of defeats one of the main advantages of a holographic sight. I don't notice any problems at ranges under about 40 yards and I can just squint my left eye for further ranges. For $30 it's a pretty good deal though.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=399922