I'm not so sure about Button. He is good, yes, but he actually had a good car last year but was dramatically overshadowed by Lewis in 2012. The only reason he finished as close as he did to Hamilton in points is that Lewis retired from roughly one in three races, usually by no fault of his own, often from either the lead or at least a high track position.
Button had his fair share of issues and DNFs too last year (Crashed into from behind in Korea, car failures in both Monza and Bahrain, pistop issue which cost him a win in China etc.), but most of his problems were down to a poor setup (His Engineers steered his setup in a different direction to Lewis' after Malaysia, which explains the difference in performance they experienced after the first couple of races). Once he had the issues solved he was getting regular podium finishes. When he has a good setup, he can easily match anybody in a race (Though leaves something to be desired in qualifying which often leaves him caught in traffic). But, he absolutely needs a car he likes underneath him to perform, unlike Alonso and Hamilton who can work around problems. Button has exceptionally good spacial awareness too, and is one of the few drivers on the grid who can be relied upon not to cause unnecessary collisions.
Lewis is extremely fast, but can often make bad decisions in a race and shoot himself in the foot. For example, racing wheel to wheel with Maldonado in Valencia 2012, or the failed overtaking attempts he made towards the end of 2010 which cost him his title challenge. That is excluding the mistakes he made in 2011, as everybody has the occasional bad year and that is the only year where in my opinion, Lewis failed to perform, as Mclaren arguably had a car as fast if not faster than the Red Bull for the later part of the season. 2012 was equally a bad year for Button as Lewis had in 2011. He did get shafted by Mclaren in 2012 though, that should have been his year. I can't blame him for leaving.
Either way, I don't think either Button or Perez can do anything in the current car. It's like 2009 all over again, the car is a dog and needs a lot of improvement, which i'm confident Mclaren will deliver. The Mercedes should be good for a podium if the circumstances are right, but at the moment Ferrari, Red Bull and Lotus are the teams to beat.
I'm hoping for some rain.
