The optical design of the objective lens differs between the NXS and Huskemaw and the other scopes mentioned by the OP. The Mark 4 and PST, for example, use a simple doublet objective lens, while some NXS and Huskemaw models use a triplet objective lens. The triplet lens gives the scope better resolution at high internal adjustments of over +/-30 MOA. I don't know what objective design the Nightforce HSV uses, but it seems unlikely it has a triplet objective at that price point.
Some of the Mark 4 models have internal adjustment ranges of +/-45 or 50 MOA. If you need more than +/-30 MOA of adjustment to get to long range, you will suffer a loss of resolution with a Mark 4 that you might not with either the NXS or Huskemaw scopes (depending on the model). This is a more significant issue for the higher magnification (>10X) scopes, because the aberrations in the objective lens are magnified by the erector tube optics. For magnification settings below 10X, the aberrations in the objective lens are hardly noticeable.
You can overcome this issue to a large extent by using a 20 MOA rail or Burris Signature rings with offset inserts. That way you can get 40 MOA of bullet drop with the scope internal adjustment set to about 20 MOA of bullet up. Your zero will be at about 20 MOA of bullet down adjustment. At these settings, both doublet and triple lenses will have similar resolution.
Otherwise, the Mark 4 scopes have good stray light management that gives them high image contrast. In that regard their performance is similar to NXS scopes. Huskemaw scopes have good contrast, although not quite as good as the other two, IMHO. The Viper PST scopes have below average image contrast for their price point. For big game hunting, I would recommend getting the high contrast scope.