Some have mentioned the NP losing weight as it goes through the animal, it was designed to do this from what I've read. The intent was for a lot of damage on impact and the initial contact with the vitals, then the rear partition continuing it's path through the animal. Is this good or bad? Well it depends on what you want the bullet to do and what you're hunting in my opinion. My desire for the higher weight retention was having the .300 as second rifle to the .375 for Eland. With the size of those big buggers, I'd prefer to have that weight retention. But above that accuracy is my first preference and for that accuracy to hold over multiple shots.
For me the NP has never let me down. I've only recovered one bullet and that was the rear section of a 160gr out of my 7mm on the Shiras moose I killed. That was found under the offside skin after cracking through a rib on the same side. The moose went about 15 feet and dropped dead after the shot. Yup, the weight of that section was 80gr, 1/2 of what it started at. Did it really matter? Now a Shiras moose will run about half the weight of a full grown Eland bull, but if they're typical of most African PG species, it won't have near the skin thickness not to mention the amount of hair.
But like I said, shoot what works for you.