pretty limited -simmons,weaver,burris and leupold seem to get the most action from what i can tell. have all of them and no failures yet, however i dont have them on the real boomers either. I like variables but have a fixed 2x leupold on a 44 mag super redhawk that has done some amazing work for me out to 150 yards.
nothing wrong with a red dot- I have to keep my shots 100 yards or less because of the size of the dot on the target.