Clarity of glass is more important than magnification. A Kowa 553 is better than Vortex 65 and 85... With mirage, magnification only makes it worse. And, the too end of all scopes gets mushy compared to the sweet spot.
I find I do most of my spotting in the 20 to 30 range regardless of the spotter. My buddy with a Kowa 88 spots in the 20 to 35 range.
I can spot at 1000 with 12x binos on a tripod, so it just depends on what you want to do with it. I can't see impacts on the target as clearly as a spotter, but I can call hits and misses.