NADs are great amps. I did not do a direct comparisons of my grade and the higher up amps in the NAD line. But I understand from the ecoustics.com forum that the difference between my C352 and the higher end NAD was worth the price of admission. You will find better replies to NAD products in that forum. I see more NAD/ROTEL users in that forum, than here or asylum.
My personal experience is, use the POWER AMP section of NAD integrated amps with a different preamp. You will be amazed how good the amps are. Their amps are compatible with passive preamps, and that is what benefitted me in the first place. NADs are affordable compared to other brands, but they make great sounding amps!! My reply may not have helped you, but at least you know you are headed in the right direction :-)
My personal experience is, use the POWER AMP section of NAD integrated amps with a different preamp. You will be amazed how good the amps are. Their amps are compatible with passive preamps, and that is what benefitted me in the first place. NADs are affordable compared to other brands, but they make great sounding amps!! My reply may not have helped you, but at least you know you are headed in the right direction :-)