Had both, and sold both. I am super picky when it come to tracking, and neither the MK5 or VX6 track as well as an ATACR. MK5 is close, but not as good. My VX6 had two mechanical failures in addition to not tracking as well. Leupold's customer service is awesome, so the issues where taken care of immediately. I have no idea how nightforce's customer service is, I have never needed it. For me, an extra 10-12 ounces for absolute reliability is a small pice to pay. That being said, if a lightweight F2 ATACR was to be made, I'll be the first guy in line.