The Crossfire is made in China and gets mixed reviews, the Diamondback is made in the Phillipines (I think) and rates with the Burris FFII, Leupold VX2, and similar, the Viper is Japanese made and rates with scopes in the $500 and up range. The models above that, I am not familar with. Vortex is a brand name of Eagle Optics which has been around for a number of years. Their Customer Service is said to be as good as the best. I hae not had need to try it out, so really can't comment. I have one Viper and one Daimondback scope, and have been pleased with both.