MC2 is the re-incarnation of fused disc, as in a plastic 'liner' coats the inside of the aluminum sheath and holds the discs in place. This makes the cable less likely to kink and crack and requires a special coring tool to be able to put a connector on. Also MC2 comes both jacketed and not, jaceted being the most common and adds to the durability of the cable itself.
Short of the differences in connectors, on spliced plant that is, the only way to tell by eyeballing it are the connector types.
Out of the 2 types, MC2 is preferable, at least in my opinion, and I have built/spliced/turned on systems using entirely MC2, the last biggest project being Wayne NJ Cablevision system. Hope this is the info you are looking for and helps you out.
