Way back when NAD 1st came on the scene, small package, low price for power rating, beautiful designs, punched above it's weight.
My audible impression was they were doing some un-acknowledged limiting to be otherwise impressive. McIntosh has power guard, but that only kicks in at the top of their truly powerful amps, NAD seemed different.
I have no idea how their equipment has evolved since that time.
I was in a hi-end showroom, listening to Jeff Wayne's War of the Worlds, via McIntosh and evidently in-efficient speakers. I specifically wanted to hear Richard Burton's voice out of those speakers. I noticed, the salesman was actively messing with the volume to keep the amp's power guard lights from flashing. Forget those speakers.