Couple things. It's new. It likely needs run in even if it's not mentioned by the maker so reviews should be taken with a grain. The other is that anything warmer than a DX90 is not for me. Of course the Calyx may end up similarly warm and perhaps just different than some other top players. It's personal but warm in the lower registers like an x5 wouldn't be favored by me.
Not sure about the SG demo unit, but FYI the one I tried in Hong Kong definitely didn't seem too new - visible wear and tear on the exterior (and hence my earlier comments re disappointment on the casing material). Don't know how long or not long it's been run.
IMO the M is definitely warmer than the DX90 when I a/b them during the demo. The thicker sound does have its appeal and slow jazz/pop sounded very pleasing but didn't like how the classical/instrumental tracks sounded, will try some synthesized electronic music next time.