since we're discussing an EU fight. Let's look at it this way.
It depends as to which luke we're talking about.
ANH Luke would not have lasted 5 seconds.
Luke from ESB is little better than a boy with his fathers sword. He's pompus, thinks he's invincible, and has little idea as to what he's doing. Vader whooped his ***, and Maul would have as well. At this point, He's just as aragant as his father was when he fought Obi-wan.
Jedi Luke is a little older, and a little Wiser, tempered by expierence and practice, He's atleast On Par with Obi-wan from Phantom menace, if not ATOC, in Skill, and patience. Maul Fighting Luke from ROTJ would be a fair fight, and Could go either way.
Grand Master Skywalker From the EU Is the most powerful Jedi who ever lived, He'd stomp maul in a heartbeat.
Personaly, the fight I'd want to see
Is Maul Vs ROTJ luke. It's the fight that would last the longest, nd be the most enteresting.