Hm, this is pretty hard.
Round 1: Anakin.
Round 2: Luke.
Round 3: Luke.
Nothing of Luke's saber skills really impressed me up to this point, however I would think his knowledge in the Force would surpass Anakin's. And, then when it ultimately comes down to it, I'd say Luke would take it. Seeing as if it would go on for awhile, Anakin has the chance of losing his cool, and not thinking straight as he tends to do, whereas Luke didn't strike me as such, except for his crazy battlecry during ROTJ.