I’ve got plenty of both and I would argue that it depends on the intended use of the scope. For a hunting scope, Leupold glass and coatings are much better than the Vortex Viper series. Vortex makes really good scopes and they do track well, but their coatings leave a LOT to be desired in low light conditions typically seen in hunting. Especially in cases where the sun is setting and the hunter is looking back into it. Vipers wash out where Leupolds don’t. Leupolds also tend to be lighter which matters to me in a hunting rifle. For a target rifle, the Viper is going to offer more features for the money, but I’m spending my money on Leupold 10 times out of 10 for an under $500 hunting scope. Unless of course, I can find the aforementioned used Zeiss in the same price range.