The contacts on MC4 connectors are shrouded, so it's pretty hard to connect yourself across the panels accidentally. MC4 connectors do have current ratings and while you can buy high rated connectors (they aren't very common and aren't all that cheap) it's not just the connectors on the solar array leads, it is also the MC4 connectors on the SCC that need to be thought about. High current SCCs that have MC4 connectors usually have multiple inputs.
Screw contacts puts more risk onto you to work safely, but a variety of terminals exist to handle what ever current you are dealing with.