At this stage of his career, Federer definitely prefers to confront big hitters on slower surfaces.
I think Fed prefers not as quick and low-bouncing surfaces as people think,
but it's not a matter of big hitters at all imo.
Against Del Po it's better for him having fast courts to move him.
And against Berdych a fast court is better because he needs to protect from Berdych's return : yesterday's match between Murray and Berdych showed how dangerous/lethal their returns are on this surface, esp. for Fed.
Against Tsonga obviously it's better playing on a slow court for everybody.
Anyway I disagree with most things people say on what they call "big hitters" on MTF