Here's an article from the CCTimes about analyzing managers in Bill James's latest handbook.
"According to a new book by James, Alou summoned 438 relievers last year; Bochy brought in 475.
Alou had 22 so-called quick hooks (pulling a starting pitcher early in the game); Bochy had 43.
Alou left starters in for nine long outings (120 pitches or more); Bochy did it five times."
Obviously the composition of the roster is just as (probably more) important than the manager in determining those stats, but still interesting.