I disagree with the Mk4 notions. I've used 8.5x25 Mk4s alongside NXS 22x & 32x for quite awhile, and the Mk4s are superior overall. Same glass, but way lighter than NXS, and Mk4s are actually MOA in adjustment, where NFs are not. Also, the Alumina flip-ups put whatever you stick on a NF to shame.
With the NF, I also run into an optical condition where eyepiece adjustment for focus reduces power a great deal. With this, the 32x NXS, adjusted for my eyes, exactly matches a 25x Mk4 also adjusted for my eyes. My eyes are tested twice a year due to profession, they're average, nothing weird.
I've tested the hell out of my scopes, and it is my Mk4s that are most accurate in adjustment, and zero return.
I do like the services provided by both companies. But my scope choice goes to Leupold Mk4 in second focal plane.