For me ... eye box size is really critical. I've found the Leupold Mark 5 (5-25) mag'd down to 21-ish ... is perfect for the long distances. The slightly reduced magnification helps an already generous eye box to give me a great target view. And I can increase to 25x for the distances past 1,000 yards. The higher the magnification, the less-forgiving the eye box (generally). First purchase was a Vortex Golden Eagle that went to 60x ... I thought "more is better" ... but it was almost impossible to use after the mid-20's. Incremental stop prior to the Leupold was (is) an Athlon Cronus BTR 4.5-29 that's pretty good too, but not as big an eye box as the Leupold. This is my experience. YMMV