I shot in the National Rifle League Border Wars South Central Finale today, after which a couple shooter-friends asked to look through my Kahles. The three of them were shooting a Nightforce ATACR, a Vortex Razor G2, and the 3rd, a Tangent Theta. The Kahles and the Tangent are exceptionally similar in clarity up to ~20x, but at 25x, the Tangent does resolve mirage boil a little better - I’d observed that in comparison before. The Tangent shooter had upgraded from a Razor G2, and claimed he notices these scopes are clearer and crisper, but his scores really haven’t changed. However, the Nightforce ATACR shooter and the Razor shooter both instantly flinched out the same “oh wow, that’s super clear!” when they got behind my rifle, viewing disgusting mirage boil in 15-20mph winds, trying to disguise targets out at 1000yrds. These ~20min or so spent by highly skilled and experienced shooters, playing monkey rolls behind 4 rifles, prone on a firing line was a confirmation of consistent observation - the ~$4500 Tangent Theta lead the pack but maybe not tall enough over the $3500 Kahles, both of which stood tall over the $3500 Nightforce ATACR, which stood as tall itself over the $2800 Vortex Razor G2... which in itself is a phenomenal optic, considerably worth its cost over most optics in the market, so this is no knock on Vortex Razors - I know I could shoot the same scores on any day with any of these 4 scopes, or even with my $1400 Bushnell DMR II (which is why I own 2 of them, AND an XRS II).
But as I have said above, even at the highest of high quality of optics, more money typically does buy notably improved performance. Just a matter of whether you need it for your application or not.