My furler has only failed once, the route
of the line was not straight in so it all jangled and locked up. It wasn't difficult to drop the sail anyway, once the decision was made.
It is hard work hauling it back up again, a two man job really.
It's not a furler or nothing, but the clean edge to the sail, the one man side of it, the easy reefing as winds get stronger, all make furler's the way to go.