AR rifle or carbine?
We just put a 1-4x on a flat top carbine with front sight tower. The scope was a an older Leupold variable in the "II " class. Bamaboy used that scope on another rifle as well in 3 gun, and hitting a 9" pieplate at 200 was not difficult, more X power is not really needed. I'd think that would equate to a 'yote or deer boiler room. I don't want a bigger scope on a carbine.
But its your rifle...you want more x's, OK. A full rifle could certainly take more glass and not be cumbersome.
Redfield is now a branch of Leupold, and I have heard nothing but good stuff, but no personal experience. The "battlezone" Redfields I've looked through had reticles too fine for field work I thought....mil dots more visible. Again, on a personal note, the Nikon BDC with its little loop holes does not appeal to either, not precise enough to suit...but thats me.
If your AR has a sight tower, you will need something to get the scope high enough to stay out of the field of view. HIgh or Xtrahigh rings are needed. The PEPR, or the Nikon 223 series works well. Those mounts also get the scope far enough forward to get proper eye relief too.. The skys the limit on AR mounts......the above models are affordable, the Nikon stuff about $50.00.