Disclaimer: I am not usually a fan of NMM, and I usually avoid giving feedback about a paint job I will never have the skill to pull off myself. However, my take on it:
The sword and armour of the knight look great. The sword in particular looks awesome to me. Actually, the more I look at it I think the silver armor looks just as good. Wish I could do that!
The non metal stuff really pops, in a good way. The purple, green, and red are all smooth and highlighted well.
Hopefully Constructive Criticisms:
The green is highlighted with too much white. It looks fine on its own, but the red and purple are not highlighted to the same degree and next to each other it looks off. I would have used more yellow than white when brightening up the green, or maybe just not highlighted it quite as much, unless you take the red and purple to the same stage. I hope that made sense.
The red and gold armor of the horse needs a little work. It just looks like red and yellow to me, rather than NMM. The similarity of the horses tail to the gold armor illustrates this I think. Most NMM jobs I have seen are done by painting the armor with the light highlighting it from a certain angle, just like you did with the sword. It looks like you highlighted the gold and red armor all over, which makes it look just like anything else painted yellow or red.
Finally, I really don't know about the colors. Everything on its own looks great, but it's hard to keep your eye on any part of the model for long.