FACT :
Marklin and ESU are not friends at all, but fierce competitors in the digital equipment field !
WHY :
ESU totally ripped off Marklin who paid them to develop the CS1, and Marklin systems, including MFX, whilst ESU also developed the Ecos alongside and the old boffins at Marklin made the agreement so loose, that huge omissions in that agreement allowed ESU to "do there own thing" in parallel IE; the Ecos and after much angst and a new agreement, M4 (mfx) [thank goodness for that

]
RESULT :
An embarrassing underdone CS1 that was totally Usurped by the Ecos, in that it did not have S88, or booster connections, or a turntable page just to mention two (edit three) deficiencies.
Fortunate/unfortunate result for CS1 owners, ESU's "Central Station Reloaded" which us CS1 owners had to pay more money for when that was already developed, but at least we got a new Switched Mode Power Supply and a stylus for our money, the firmware, M had already paid for and was already operating in the Ecos, but we paid for it again
RAILCOM, developed by ESU and Lenz, and owned exclusively by them, and could be licensed, but Marklin would not do that on principal ! IMHO
I have seen it work and it is good
WHAT THE NEW M DECODERS BRING (IMHO) is; more functions and programming possibilities (and a better programming tool than the earlier one)
MFX+ has, and will always be, exclusive to New Factory Locos, so don't expect it to be available on the M retrofit decoders
I do have five or six MFX+ Loks and at this stage, and two more on order (Kl 41 37929 and 18.5 39030

) but I don't have a CS2 on order as yet

but I do think MFX+ is fun and I will include it's full functional ability into my new layout, but IMHO I think it could become just a tedious distraction after awhile
One more thing, I only own Marklin Locos

(99.9% Digital and 95% MFX

)