Go with the best you can afford. I used Leupold exclusively for 20 years and got my first NF NXS in the last 6 months. WHAT A DIFFERENCE! I have had great luck with Leupolds, but the NightForce is amazing. The only downside is the weight. Mine is on a Sendero in 300 Ultra and I kind of wanted the weight. On an Accumark, it might make balance a little off, I don't know. If you are serious about long range - 600+ - I would definitely go with a scope you can dial and then equip yourself with Ballistic program, wind meter, scope level, and cosine indicator. If you are going to limit yourself to less than 600 a reticle with hold marks will do the job. My dad shot a NV mule deer at 720 yards this year with my Sendero and the NF cranked up to 22X. He said it was like shooting a deer at 200 with his old Leupy at 10X. Good luck and Happy Thanksgiving.