I have compared it to:
1. Accuphase E-306v
http://www.accuphase.com/historys/e-306v_e.htm2. Creek Destiny Power Amp
http://www.tnt-audio.com/ampli/creek_destiny_e.htmlI entered the comparison having used the Creek Destiny with KEF LS50 as my main system for the last year, since most of the other stuff was in storage. I got the NAD M22 and the Totem Element Fire at the same time.
I burned this new system in for 10 days while I was away.
When I got back I compared the three systems by changing the banana speaker cables (Analysis Plus Black Mesh Oval 9) while listening to a few songs I used as personal references: Herbie Hancock "The River" with Corinne Bailey on vocals (24/192), Kevin Mahogany "Never can say goodbye" from Pride&Joy (16/44), Karl Munchinger's version of Pachelbel's Canon (16/44), Bill Evans' "Detour Ahead (Take 2)" out of Waltz for Debby (another unnecessary 24/192), and Daniel Hope's "I Giorni" out of Spheres (16/44). All FLAC.
In a nutshell, the NAD M22 beats the other 2 by a clear margin when it comes to accuracy and dynamics with a good recording. The NAD M22 and Totem Element Fire absolutely amaze with instrumental/orchestral music. Even when not listened loudly the dynamic, analytical yet non-tiring presentation is amazing. The Accuphase 306 is a phenomenal amp (I don't think I can part with it), and more forgiving of poorer recordings (which actually includes Bill Evans "Waltz for Debby". The NAD M22 kind of exposes this legendary recording's somewhat crude mixing, while the Accuphase blends the stage a bit more.
With voices, I think I actually prefer the KEF LS50 and Creek Destiny combo, but I think this is more about the KEF vs Totem rather than anything else. I need to do some speaker comparisons which I haven't gotten around to for now. Voices seem to have receded a bit to the back. Which is great if you want to hear more to the band, not so good if you want to just focus on the singer or lyrics. It's ever so slight, and may have to do with the KEF cleverly boosting something, but that is a separate topic that I don't think has anything to do with the M22.
The M22 combines the rare ability to provide superb analytics ("there, a mouse just farted in the right rear corner of the studio") while staying eminently musical and non-tiring. Bad recordings can get a tad tiring though, especially after you have listened to a few good ones.
The Accuphase E-306v was my amplifier reference. Until the M22 arrived.