Hello Xduoophil, you asked how the M2 sounds compared to the X2, well it is very hard to describe. People mention the fact that some units give more detail, I have a DX50, an Xduoo X2 and an M2, the X2 is good but the M2 takes you into an entirely different league, IMHO, it wipes the floor with the DX50 as well, I thought I knew all my albums and everything there was to hear, well I had to re-think all that because the M2 has shown me things I never knew existed in my recordings. On it's own, the M2 is brilliant but I took the line out and put it through an O2 amp and when that is not available, a Minibox-E, both of which improve the sound greatly but only because they have that bit more oomph to drive the headphones, if I change back to the M2 only, the atmosphere and emotion this device can portray is wonderful. In case you didn't already realise, I am hooked on the M2, dream though I may, the A&K's are too expensive for me and I suspect the M2 isn't that far away in quality, what must the M5 sound like??? OOOooooo...