I can't give any advice on the 50mm, but I do own 3 Nightforce 56mm and they are great.
I have a 3.5-15x56 w/NP-1RR recticle on a 6mm AI custom Rem 788 (varmint/target
but really wish it was a 5.5-22x56. The extra power would do more justice to the gun. I've owned this scope for 8 yrs.
I also have a 5.5-22x56 on a 7mm Rem Mag 700 w/a 30" Hart barrel. This scope also has the NP-1RR reticle. This set-up is great for 1K shooting.
I purchased this scope in 1995 for $600 new.
Last year I picked up a 8-32x56 Benchrest at Sportsmen's Warehouse for $1100. It had the NP-1RR, but I just sent it back to the Nightforce shop to have the reticle changed to the NP-R2 reticle. This reticle has verticle references every 2moa and windage references every 5 moa. I purchased this scope for my next long range gun. Which will be built by Kirby.
On all of the scopes I have a quick reference card for shooting various ranges. You won't go wrong with the Nightforce.
Hope this helps