Keeping the M:C and getting a Digitone gives you a very nice little two piece setup straight away, no mixer required. M:C can do drums/percussion, Digitone can do the synth stuff. I’ve found that although you can make the Digitone do “everything”, it gets a little cramped, not because of the 8 note polyphony limit (which is enough pretty much most of the time) but only having 4 sequencer tracks. Getting something else to do the drums allows the Digitone to shine, and believe me it does. It sounds awesome…
I sold my M:C before getting a Syntakt, the Syntakt more than replaced the M:C for my needs. I initially held off buying one because having a Digitone already, I thought the lack of polyphony on the Syntakt would be an issue. Well, it hasn’t been an issue whatsoever, I guess the Syntakt steers me towards making tracks where polyphony isn’t needed!!
I’m finding the Syntakt to be an absolute blast and it’s the best “one box solution” out of the 3 for me. You’ll have a good understanding of how the machines work, coming from the M:C and it is amazing how much content can fit into 1 pattern because of the 12 sequencer tracks. The analogue machines complement the digital ones very well too, adding a different flavour to the sound whenever you need it.
All of the Digi boxes are completely safe bets imho, you really can’t go wrong. No help whatsoever I’m sure but that’s how it is my friend!