"AO" means Adjustable Objective, it basically works like focusing a camera.
Do you need to focus your scope? Maybe, it depends.
Let me explain a little.....
Close shots (under 100yds) probably need the objective focusing, but if you're hunting how much time do you have at under 100yds? So, based on that if you either hunt beyond say 75 yds, don't target shoot under say 50 yds, & don't mind backing the magnification off a bit (focus gets less critical as you reduce magnification) you don't need an AO scope.
However....... if you want to target shoot with real accuracy (sub MOA talk here) the AO reduces/removes something called parallax. This is a good thing as long as you take the time to mess with the adjustment. Unfortunately the marks are at best, approximate. To really get best bang for the buck from an AO scope you need to trim (adjust) your particular scope. Does it work? yes. Do you have a use for it? I don't know, maybe you do. Can you just dial in a marked range & get some improvement, yup. Is more possible with a bit more work, again, yup!
