The MKx/CMC6 combo is a full-size small diaphgram mic, with fairly lengthy (5"?) CMC6 mic bodies. Because the caps are a separate piece from the bodies, a whole range of pickup patterns are available: MK4 (card), MK41 (hyper), MK21 (subcard), MK2 (omni), etc. To run this combo stealth, though, you'd either have to:
[a] buy the KC5 active cables to run the MKx caps remotely and then carry the CMC6 bodies with you, or
buy a pre that allows the caps to be run remotely from the CMC6 bodies, like the JKLabs or NBox preamps.
The CCM4s use a different design to achieve the same function as the CMC6 bodies + MK4 caps - the full size bodies are replaced by much smaller electronics housed in a much smaller space. And the pickup patterns are not changable. So if you want the option of running cards or hypers, you'd have to buy a set of CCM4 (cards), and then also a set of CCM41 (ypers).
If you don't mind sticking with one pickup pattern and stealth a lot, the CCM4s (or CCM41s) are a great option. If you want the flexibility to run different pickup patterns, the MK4/KC5/CMC6 combo is the way to go.
I wanted the flexibility to run hypers or cards, so I bought MK4 and MK41 along with the CMC6 bodies and KC5 active cables.