I work in a shop and have tried a lot of stuff, sights included. The Cobra I don't like because of some of the reasons already stated. That, and I don't like the chincy way it's attached to the mount. Last year I looked for a couple months at some of these things and decided on the HHA OL 5000. I know it's more money, but you'll only have to buy it once. It's all metal, bright as your eye can percieve, built like atank, micro-adjustable for windage, and Lifetime warranty.
One thing I never compromise on is accessories. Good ones will last a long time and not give any trouble, such as noise or plastic breaking.