User blog comment:JThan9/Magic World Deck/@comment-24032262-20140215232316/@comment-4292163-20140216013036

Belials's defense is only 1000 lower, and in exchange he deals an extra damage per turn, he doesn't need to destroy by battle (so no Dragoenergy or Battle Spirit Unite), his effect works if your opponent doesn't have a center monster (due to using a weapon), and if you don't want to deal damage you can destroy your opponent's entire field instead.

I like Marbas' art way more (mainly because I'm a programming student), but I'm pretty sure he's weaker than Belial.