Whose the worse pitcher: Zito or Willis?

I gotta say, I'd rather hand the ball to Barry Zito. Besides this season and last season, he's shown himself to be the better pitcher over time, and he's shown flashes of that skill, decreased velocity or not. Willis is skilled, but had one powerful season along with some crappy ones, he has a lot of work to do if he intends to be a consistent major league pitcher.