A little late but I just wanted to add some input for those who might be looking at these scopes.
I was looking at these two and was torn on which to purchase, so I purchased them both to see which I liked more.
I am very new to this whole thing so I do not know about all the minute details about the internals of the scopes etc.
I ended up going with the Mark 5 for the following reasons,
Turrets:
The Mark 5 turret clicks felt great and sounded great as well, better imo than the NF. So if you are looking for audible, clicky turrets the Mark 5 wins.
Illumination:
I definitely preferred the illumination adjustment on the Mark 5 over the NF. On the NF there is a button that you have to hold down to adjust illumination as opposed to the turret style illumination adjustment on the Mark 5. My personal preference was the Mark 5.
Indicators:
Additionally, on the Mark 5, I really like the metal prong that pops up on your second revolution, giving you a tactile indication of where you are. The NF did not have this indication from what I recall. Remember I'm new so maybe I missed it.
Clarity:
As far as clarity, I preferred the Mark 5.
Customer Service and Company Reviews:
I had read in many places about NF's customer service not being great. Of course, I do not know how their customer service is personally, but I was not willing to chance it after reading the number of negative reviews left by others. I read more positive reviews regarding Leupold's customer service. I did have experience with their customer service and it was great. This was very important to me on my decision, that is, how well a company treats its customers.
I hope this might help others who may share similar preferences which I think it comes down to when choosing between these two ie, personal preference.
More Details for those interested:
Reticles
Being new to this, I wasn't sure about which reticle I would like between a clean reticle or a tree reticle, so what I did was ordered a tree reticle on the NF and a clean reticle on the Mark 5. On the NF I ordered a Mil-Xt, and on the Mark 5 a TMR. I ended up preferring a cleaner reticle, ie, TMR. However, I'm sure the Mil-Xt is really awesome for certain shooters. Being new, I wanted to start with something simple and clean. Maybe in the future, I will go with a tree-reticle. Just a quick not regarding Mil-Xt reticle, I wasn't able to see the holdover dots very well until really zooming in, maybe around 9 or 10 power, I can't remember exactly, but just remember thinking, "wow, you really need to be zoomed in to be able to see clearly the holdover dots".