Malgus loses sabers because Bane can ward off his offensives to the head and joints and Malgus's blows will be repelled everywhere else. Malgus is durable, but not to the extent of the Orbalisks.
Probably still Malgus for Force, though.
All-out - I see it as taking a very long time for Malgus to win through Lightning or for Bane to kill him in sabers via outlasting him, but I think it's safer to say it could go either way.