It'd be a helluva battle, but I think Jedi Anakin would ultimately lose to Maul. I won't draw from novel sources that I haven't read/remembered, but judging from movie showings, I'm not very impressed by what little we saw of Jedi Anakin's combat prowess.
And ditto the "helluva" descriptive for Vader vs. Maul, but I see Vader winning. A far more masterful defensive swordsmen than Maul who had the bonus of 13 years on-hand experience and knowledge of Vadakin was steadily losing the battle of his life every step of the way. I don't see Maul lasting as long, but I do see the entire encounter being far more aggressive and destructive.
Clear-as-a-bell and fresh-from-his nap Zonakin would do to an equally-rested Maul in 30 seconds what he did to a tired Dooku in 5.
__________________ I did not hit her, it's not true. It's bullshit. I did not hit her. I did naawwt.
Anakin and Maul are similar in that they are both primal, vicious combatants with technical skill that rivals their ferocity. Maul is a master of Juyo, which requires its users to be "high end masters of multiple forms" and Anakin/Vader is said as early as The Rise of Darth Vader to borrow techniques and maneuvers from all forms of lightsaber combat. While Maul enjoys a definite advantage in athleticism and martial arts, and a probable advantage in pure technical ability, even his enormous endurance is outclassed by Anakin's unique resistance to combat fatigue, which outstrips even those similar powers afforded by the Sith (at least in the form of Count Dooku).
Maul's Force powers aren't known to be prodigious, but his battles in The Phantom Menace depict him using precise applications of telekinesis (manipulating the severed droid arm to open the doors to the shield generator room, giving him more room to maneuver against Obi-Wan and Qui-Gon; and his sudden Force push that toppled Obi-Wan into the melting pit). Anakin is not shown to be nearly as precise, but his powers, which are tethered so closely to his emotions, are potent when unleashes.
Tl;dr version: Maul is more skilled as a duelist and fighter; Anakin is stronger physically and in the Force. And as we know from Kas'im and Bane, this could be surprisingly close.
Jedi Anakin is a winner, i think. But it would be a good fight. Sith Anakin (before Mustafar) can destroy Maul. Anakin (a few months after Mustafar) isn't even close to Maul. And Sith Anakin (one, or few years after Mustafar) is a little better then Maul (far better with the force, and weaker with saber).
It depends of the point of view. In my opinion ROTS Jedi Anakin is more close to Obi-Wan, and just like his master, he wasn't able to defeat Dooku. Only his aggression, anger and hate let him defeat Dooku. In novel he is just better, but in the movie... as jedi Anakin, not really. He fight with Kenobi on his side and can't breaks Dooku's defense... + he gets two kicks (first in a face - we see Palpatine's face i this moment, if i good remeber). So - for me - Anakin in a second half of this duel, fight like a sith - not jedi. And definitely he is in the best mental condition. Yeah, Anakin from duel with Dooku >>>> Anakin form duel with Kenobi.