Except the M51, which got a bad review from Amir. I have one. It still sounds great enough for my ears. But resale value took a hit.The NAD Masters series have maintained a very good resale, have proved reliable as far as I know and they've maintained the matching aesthetic for the last 20 years. I remember when I first saw the series in 2003/4 and figured, this is a game changer for NAD as long as they stick to it. They did.
But it should possess all those attributes at the price.
No hard feelings Amir ;-)
Seriously, I find NAD offer quite interesting : BlueOS is very pleasant for daily use (I use it for years, with a mix of NAD and Bluesound), DIRAC is a clear added value, and now Purifi modules with improved PS.
What could one want on top?
Lower price, sure.
But I purchase mostly second hand. ;-)