Most scopes will do ok until you get to tough conditions, or until after they're knocked around a little for a couple of years. That's where the good scopes show the difference - low light conditions and durability. Take a zeiss and a ncstar outside at dusk and you'll see the difference. That's maybe both ends of the quality range, but the difference applies across the range.
My brother missed an elk last year at dusk about 350 yards out because with his low end scope he couldn't pick it out of the juniper. It was clear in my Zeiss from 75 yds farther away. That's when the $100 - 200 saved seems like a mistake.
On the other hand if you're a casual plinker/small game hunter, anything but the very cheapest will probably do ok.