My 2 cents , have used Tasco , Bushnell on rim fires . Weaver , Redfield & Simmonds on centre fires .450 bigbore , 30-06 , 300 H&H . I recently bought a Swarovski for my new .378 Weatherby . As far as optics , I have never once had a scope fog once , wether hunting deer , moose , elk or caribou or routine squirrel or hare . However , I am religious within firearm mtce & proper storage & handling . The actual purchase of swarovski scope was more for durability reputation rather than shear optics quality . Neither of the previous mentioned scope manufacturers ever failed me over the previous 50 + yrs !