Setting? If it's on a platform over some huge drop or fatal material of some sort, Vader easily. Saber fight, not so sure, but I'm leaning towards Vader.
Remember that at this time Vader is conflicted iside. The soul of Anakin is starting to fight back. I say Maul wins just because Vader wouldn't be able to keep up with him. After all, Maul almost beat Vader in a fight once before and that was when Vader wasn't conflicted.
There is no chance in hell Maul would beat Anakin (Vader). Obi-Wan managed to cut Mauls saber in half (which was a potential killing blow) and keep him on the run when he was a padawan. Anakin is WAYYYYYYYY above TPM Obi-Wan....lol Anakin is just below Yoda and Mace in the entire Jedi order in terms of saber combat (and arguably Obi-Wan but its not as cut and dry as with Yoda and Mace)
Vader would tool Maul, then crap on his mangled corpse.
It's all about the setting. Vader could Force Grip him and throw him off the edge if it was that kind of setting... Actually, he could fling Maul into a wall as well, and if he's lucky, knock him out.
Even considering the Infinity, Vader (according to the Prophets) was emotionally conflicted inside. It's possible Maul was aided by Dark Side prophets.
Anyways, Vader does cut his saber in half. Luckily for Maul, he cuts it at the exact spot where it'll form dual sabers >_>
And let's not forget, Vader does win. He took a hit through the chest and just walked away.
Meh, Maul' take this. Vader is neither fast enough to withstand him in lightsabre combat, nor is he good enough in the force to actually try and harm Maul with it.
Registered: Sep 2005
Location: Picking up some power converters.
Vader is way more powerful with the force than Maul. In a saber fight, it would be tough, but Vader would walk out. Physical strength counts for a lot in a saber fight.