Don't tell Andy, but the M2s feel more solid, probably due to aluminum frame and glass front & back. I'd honestly prefer that M2s had an aluminum back, though. More durable than glass back, which pretty much ensures you'd want the case. N3 doesn't really need the case because it's got the nice textured pleather type back.
M2s side buttons are okay. Probably a step above the more plasticky buttons on the N3, but I actually think I prefer the buttons on the Shanling M1 over both M2s and N3.
I need to use the control knob more to see if I prefer it to the control wheel the other Shanling DAPs have, but so far I think most people will prefer it. Scrolls quickly and has been pretty accurate so far. The downside is that there are no dedicated volume buttons, so if you need to control volume while in the menus you'll need to return to the now playing screen.
GUI will be very similar between N3 and M2s, since both were developed by Hiby. I'm very familiar with both Cayin and Shanling GUI, so both are pretty easy for me to navigate. That said, I give Shanling a slight nod in the GUI department for various minute details. I should probably chat with Cayin about that...
Regarding sound, it's too early to tell. Still getting to know M2s. My gut tells me the N3 will be the more neutral/reference type sound, whereas M2s will be a more full, smooth, musical type sound. Need more time, though!
