I love the MK5, personally I think it's the one of the best values in optics today. I know their reticles aren't for everyone, but I have largely standardized on the H59 so they have that covered for me at least.
I've got one 2.5-20X NX8 I bought on a whim, and as some mentioned above it isn't great IMO. It's on a lightweight mountain rifle so it will probably do but under no circumstance would I pay for another one. That thread lays everything out in much greater detail than I care to, but frankly it was so disappointing that I haven't wanted to try the 4-32 which seems to get better reviews. On paper it's perfect, and I should have known that feature set at that price would have some serious compromises. My biggest gripe is the very unforgiving eyebox and depth of field. Shooting in the prone at the range to get data I didn't have these issues but when I took it out into the field in suboptimal shooting positions and target distances constantly changing I felt like I was fighting the scope constantly. I actually went back to a rifle with a Mark 5 mid-trip and just didn't have those issues. I love the Mil-XT reticle though, that thing is legit.
I am of the school of thought that scopes with high magnification factors are a parlor trick at lower prices, and you basically compromise some really important performance characteristics to go 7x, 8x, 9x, etc. for a marketing blurb. I kind of figure if I need 20X I am unlikely to need 2X. Just because Hensoldt can pull it off for $8000 doesn't mean Nightforce can for $1900.
TL;DR: I'd rather have a high-performing 3x-5x than a marginal 7x-9x for the same cost.