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 ass, 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.