I find SyncDiscs very useful, because you can get it not only to copy what is missing on the target disc, or in need of updating, but also to delete anything extra that it finds there, so that you end up with an exact copy of a set of files or directories - which is often just the result I want; and it means I don't have to think how to get it. For this, I am prepared to wait, or make a cup of coffee, while it does its stuff.