The two LA teams are loaded with stars, but their pitching isn't great after the no. 1 and 2 starters.
It's always the pitching that's the difference, but it's hard to tell right now who will have the best pitching. It depends on injuries and who is having the best season. For example, if the big 3 come back in Philly, they will be tough. Halladay will have to return to form. The Sox aren't bad with Lester and Buchholz if they return to form and somebody else shines. SF always does it with pitching, but Lincecum is a big question. Toronto could be good, but Johnson and Buerhle have to be strong. The top 3 starters are so important, especially in the playoffs. The team with the best top 3 is usually the team to beat.