I just got the ARE-C2 charger today together with 2 ARB-L2S 3400 mAh batteries: from the outside it is really identical to the MCC-4. The only difference I have noticed so far is that the sticker lists fewer Lio-on lights for compatibility - 18650, 16340, 14500, 26650 while the MCC-4 on the sticker lists additional sizes. Also, the ARB-L2S lists fewer certification symbols on the sticker too.
It's quite big for a charger, at least for me as all my other chargers (from Nitecore, Fenix, and Klarus) had only 2 bays. Not a travel charger if you like to travel reasonably light. Other than that, the voltage display is a great feature and it seems to charge batteries quicker than anything I was using before!