I have had the NX8 mil reticle for the past 3 months. Previously, my LVPO was the Vortex Razor Gen II HD 1-6X and I acquired the NX8 precisely because of weight. The NX8 resides on a LWRC DI 16 inch upper, with a POF lower.
My thoughts:
PROS-WEIGHT & SIZE: Yes, it is noticeably lighter and shorter in length than the Vortex. However, to capitalize on the weight reduction, you have to invest in a light mount or else it will still feel heavy. My first mount for the NX8 was a Larue 1.93 in (
https://www.larue.com/products/larue-tactical-spr-m4-1-93-mount-qd-lt135/). Although a good mount, the QD lever interfered with my charging handle.. The NX8 has a smaller eye relief than the Razor HD and so you have to mount it further back. If you get the Larue, don't choose the QD option and go for the VFZ option (no lever). I ended up using the Larue to mount my Razor HD and it was fine because of the longer eye relief. The scope mount that my NX8 lives on is a Geissele super precision scope mount 1.93 inch. The mount is light, rock solid, and does not interfere with the charging handle. I thought of lighter mounts (i.e. Aero) but read of some durability issues. I also chose 1.93 inch because my previous 1.5 inch scope mount (Bobro engineering) had me bend my neck too much. The 1.93 inch feels much more natural with less neck strain.
PROS-OPTIC QUALITY: The first focal plane is awesome and the red dot is truly daylight bright at the medium setting. I am not a optic expert but I think the 1X feels true to 1X. If there is a difference then it is very very slight and not practically discernible. I also prefer the NX8 reticle over the Vortex HD reticle. It just seems less busy without the vertical line from 12 to center.
PROS-EASE of ADJUSTMENT: the 1-8X moves smoothly and easily with the included lever. As you all know, the Razor HD ring is stiff as heck even with an aftermarket lever.
CONS-EYE RELIEF. The shorter eye relief is only a problem in regards to the scope mount as above. Otherwise, it is not an issue during usage. I did not have any problems acquiring the reticle dot in two carbine classes.
CONS-RED DOT SIZE WITH HIGHER MAGNIFICATION: since this is a FFP scope, the red dot enlarges accordingly with higher magnification. It does obscure the target if you are aiming for something very small. If you are aiming for just center mass, however, then it is not an issue.
CONS-OPTIC RING & EYEPIECE: Like the Vortex, you can focus the eyepiece to your needs and lock it with the optic ring. On my scope, the lockage kept coming loose during firing and I have had to readjust it. I have never had to re-tighten the eyepiece on my Vortex HD. I emailed Nightforce and they said to wear gloves and really crank it down. I applied some Pipe thread sealant tape and tightened it again. So far so good.
USAGE: I have used the NX8 in two carbine classes so far and it has been wonderful in both. The first class was a low light carbine class and it was crystal clear and bright with my Scout M600 1500 lumen weapon light. Yardage was 100 yards and in. The second course was Aaron Barruga's Guerrilla Approach Functional Marksmanship Movement (FMM) Carbine class (50 yards and in). This was a movement intensive class with the carbine with rapid sprints, prone to standing, and target transitions. We ran a lot. There were some drills where the losing team would have to run five 100 yard sprints with their rifles. This all added up. On day one I used the NX8 but switched to my MRO on day 2. I switched not because of the NX8 performance but for two other reasons: 1) we did so much running with the rifle that I honestly got tired. 2) I wanted to see how a red dot MRO would do with all the running and we had a night portion. Since I used the NX8 on the last low light class, I wanted to see how my MRO performed at night with a weapon light. I have to admit that running around with the MRO was so much easier than with the NX8 (as light as the NX8 is, I cannot imagine running around with the Vortex HD). My performance was the same with the NX8 and the MRO in terms of accuracy and speed of sight acquisition. The solution I know is to be more fit and stronger. I am relatively fit (7.5 minute mile, 14 pull ups and 40 push ups in good form, and 4 minute plank, etc) but there is room for improvement.
I consider myself an amateur in regards to LVPO and carbine shooting in general. However, I hope that you gain some insights into my experience.