I've got a Burris FF 2 and a FF 3, as well as a Vortex Venom all mounted on Ruger MK III's. Haven't had an issue with any of them. I like the cover for the FF2 better than the one that comes with the FF3, but the FF3 has a top loading battery vs a bottom loading battery in the FF2. All three of those can be found in your price range.

"Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same." - Ronald Reagan