Chomsky is a boring hack, but you can't deny he's reasonably intelligent and generally knows what he's talking about. Zizek is a rambling buffoon.
Unless your grasp of Lacano-Hegelianism is substantially more elaborate than mine, you can't really be in a position to deny that Zizek knows what he's talking about most of the time.
He should stick to philosophy then, and stop thinking his political views are so cool and edgy.
someone once described Zizek as "the stand-up comedian of the left", adding "I never said stand-up comedy was a bad thing".