My opinion might not be worth a hoot, but I don't think there's much of a home field advantage in baseball, overall.
Of course some ballparks have distinct nuances....think Fenway Park in Boston.
I look at it more from the perspective of streaks. For example, has a team been losing home openers after a road trip? Another one can be visiting teams from the far east coast going to California/West Coast for a 3-series trip.