I signed up on this site specifically to comment on the M33. I bought one used around a month ago, and I absolutely love it. I'm reading a lot of comments here from people who have likely never heard one, which always makes me smile. I am using the M33 with Paradigm Prestige 95F speakers in my home office measuring around 15ft x 25ft. My previous amp was a Yamaha A-S2100 with a Sony HAPS1 Hi Res DAC as the source. I prefer the NAD for it's simplistic one box solution, features and yes, sound!
The M33 produces an amazing level of detail and clarity I have never heard before, but not bright at all...just very revealing. Also, I was hugely surprised by how good the phono pre-amp is! I was worried that the NAD would mess things up converting an analog signal to digital and then back to analog again...seemed like a pointless exercise. Well, all I can say is my Music Hall MMF7 with Goldring Eroica H moving coil cartridge has never sounded better.
Although I can stream my music catalogue from my PC to the M33 using BluOs I don't like to always have to have the computer on. I downloaded my hi-res music collection to a 128GB USB stick and I just leave that plugged into the back of the M33, works great! For streaming I still use Spotify as I have a family account for the kids, and then Radio paradise for some higher quality files, but truth be told the Spotify Premium sounds pretty decent through the M33 DAC.
The M33 is a well sorted integrated and really fits the bill as the high end, one box solution I was looking for to complete my minimalist setup. I think some of you guys need to stop geeking out on the Class D versus A or AB debate and just take a listen. I'm one happy camper!