I think the wise Sith would attack Superman's mind. Clearly they would be outclassed in terms of brute strength and survivability so the only option would be to turn Superman... whether that counts as a win, that's up to you, but that's how I see it panning out.
Come on guys be real with your polls! The only weakness superman has is Kryptonite. Ring a bell? I don't see any kryptonite sabers in Siths. This clearly shows that Superman is the winner. (Not to mention his steel skin, inhuman reflexes, inhuman strength, laser eyes, torpedo breath and his bullet like speed.) Sith = OWND
Well one would have thought that an entire galaxy of senators and citizens and soldiers would be enough to overcome Sidious, but he managed to take over the galaxy by poisoning the mind... And Kryptonite is a space borne mineral... and where do Sith love to hang out? On the bridge of their Mega Annihilation Extreme Death Cruisers of course! In space. Plenty of access to Kryptonite.
I actually saw a post from a Digg link that argued if a saber could harm superman, their verdict nope and they were very convincing so Superman wins for me too.