I can forgive the somewhat limited user interface for setting these up that is in the stock add-on, but the lack of automatic syncing of rules to all computers with the same Firefox account is really frustrating to deal with.

Putting in the effort to get them all set up nicely and then having them either blown away (I think this happened once...) or needing to get that over to another computer has made me limit my use to fewer containers than I probably would otherwise use.