i am currently testing out an M10 and debating what to do.
until recently, my system consisted of Squeezebox Touch > Benchmark DAC2HGC > NAD M22 > KEF Reference 1.
i decided to go more minimalist and i like red speakers, so experimented with Squeezebox Touch > NAD D7050 > KEF LS50 (red) + Velodyne sub.
i decided i missed nothing, honestly.
the M10 adds convenience (i could eliminate the Squeezebox Touch, but really don't want to) and looks cool. i already get the cool artwork on the Squeezebox Touch screen, so it's a bit superfluous. what i really wanted to see was if the M10 would an extra layer of insight and transparency to the music.... and IMO it doesn't. compared to the D7050, in my environment (which doesn't benefit from extra watts), the sound is the same... and if i had to pick only one it'd arguably be the D7050... and the M10 has occasional hickups that are strange... occasional slow to none responsiveness that requires an inexcusable restart... and i'd worry about continued support for Spotify Connect, since this was a feature that was disabled on the D7050 while the Squeezebox ecosystem still continues strong on integration.
i also brought back the KEF Reference 1s from semi-retirement (I am about to put them on the market, may get Paradigms) to see if I was missing something and nope, pretty much all stayed the same.
my takeaway is to keep things simple and think about it as a software front end that will stay very dynamic.... services like Spotify will keep messing with their API, audio companies like NAD may not keep their old product lines updated with API changes hence separation makes sense. Something like the open Squeezebox system keeps updating the software even though the product line hasn't been sold forever. NAD didn't bother with the D7050 which doesn't forebode well for the M10, and come on, that's a $2.7k brick in your system if the support for online service doesn't keep up.
The fact that processor load interferes with measurements (as shown in this review) is also questionable.
I like the integration of DAC and amplification... even as far as thinking that acitve speakers with build in DACs may be the future... but I think expecting your do-it-all streaming-DAC-IntegratedAmp to keep up with changes is expecting too much.
As I write this, I have decided to sell the M10 and see what's next. A masters version of the D7050 without integrated streaming services would probably be a cool thing.
PS: i should add you should disable the auto-on feature on the D7050 which is garbage and regularly forces you to deal with the useless touch sensitive touch power button (what were they thinking). the D7050 is power efficient and the on and off messes it up (as it may do with the M10, i wonder if the hickups are because coming out of power saving mode)...