If you are looking for new, Leupold or Nikon is the way to go, Burris is ok stuff as far as I know of.If you are looking for a used one, I'd stay away from Bushnell ( Bausch & Lomb), Weaver, Simmons & Tasco,again, look for Leupold, and Redfield,Nikon if u can find it.
I got rid of everything except Leupold & Nikon in my stuff.