M11 is less warm and more neutral. But still not dry and is musical, I greatly prefer m11 over the x5iii 'veiled' approach.
I compared dx220 a bit back, it compares with that imo, so I would guess it's a step up. Although I've never listened to dx150.
Right with Neutron installed and its Audio Hardware setup correctly I am upsampling everything to 384khz dither enabled, outputting everthing at 32bit and using 64bit for dsp. I have an LPGT as my reference DAP, ( I EQ everything so Fiio app was disabled within minutes) i've transferred my LPGT peq settings like for like to a 5 band peq on the Neutron M11 and its not too far behind at all. I sold my dx220 (which sounded better than my previous dx150/dx200) as it was just too slow, so using neutron with highest quality audio zapped cpu and battery and wasn't a fun experience. Ok so same Neutron settings on Hiby R6Pro, very close with hiby having a little more power. I think a little more accurate detail from m11. R6pro crackles for the first few secs on neutron upsampled to 384khz but fine at 192khz. Speed of the devices pretty much identical. Better than plenue L for me (its eq is limited. freq only goes to 62hz, i use 33hz also and you are stuck with a couple of preset bands and Q width. It would be a killer dap if the eq was more configurable. Colorfly U8 is a different analogue sounding beast, awesome peq/eq. Cant really compare as its so different (in a good way) Cayin N6ii, not sure yet, i sent it straight back due to a crap light bleeding screen. replacement due in a few weeks. will be doing the Neutron test with same settings. WM1A/Z lowish power and can't get the eq to my liking. Shanling M5s - the EQ was done by fisherprice. Modded Xuelin ihifi990 - on par with fiio m11 neutronned.
@JamesFiiO please can we have a black background boot screen, its currently way too bright when I turn it on at night. Pretty please