I purchased a NAD M10 V2 earlier this week at a store with a 60 day return policy to replace my c390dd that has driven my Audio Physic Tempo 25's for the past 10 years, but has required 3 repairs the past 3 years and just died again 1 day after the last repair.
Although not 100% sold on the reliability of the brand, earlier I eliminated the Marantz 40n and Lyngdorf 1120 as I really like the NAD sound compared to those.
This time a shoot out between the M10, c399 and c658/298 combo convinced me to bring the M10 home to my own system. Yes, the latter two did sound better (not a blind test so could be biased) to me, but not good enough to go for a much less attractive form factor and higher cost of 2 units and the c399 is expected to be not available for months. At home the M10 sounds good. Different than the c399dd. A bit warmer, which is not a bad thing. With complex parts that are bassy it seems to be a bit less well-defined. Setting up Dirac took a bit of effort but was quite easy to figure out. It does take away some of the room resonation, making it less tiresome to listen to.
Although initially happy with the results, really annoying is that my M10 disappears from the list of players with no way to connect it again other than unplugging the thing and rebooting. According to NAD support it is a problem with my network equipment. If I can't get it to become reliable it is definitely going back. I am keeping my fingers crossed. Right next to it is my old Bluesound Node 2 that hasn't shown these issues over the past 4 years, so I'd be surprised if my network is the issue.
What I also don't like about the device is the flimsy remote. It feels like a toy and is too limited. Why no source select buttons? It has numerical buttons that seem to have zero use. I guess it is better than no remote on the original.