ATACR Pro's over the NXS,
30 additional MOA of elevation adjustment
Better glass that is noticeably better in low light
3x more power on the top magnification
Like the parallax adjustment a little better (quicker and no-parallax seems to be closer to perfect focus at all distances)
34mm tube and rings add clamping surface area for big rifles
3/4" shorter than the NXS
Cons of ATACR VS the NXS
ATACR is heavier
takes 34mm rings that are a bit more $
$450 more money
So it boils down to do you need the added elevation? better glass? (I always have felt the NXS Glass was plenty good for my needs, but at distances way out there the ATACR glass is nice)
I have both and see it like this. If you are going ELR the ATACR is the way to go. But for the average long range hunting situation the NXS is very hard to beat. Now if the added weight does not bother you and you have the extra $$ in your scope budget, then the ATACR is a very nice upgrade over the NXS. But I am only using the ATACR on my ELR rigs.
Here is a full review I did comparing both to each other.
Nightforce ATACR Scope Review