maple bats are extremely hard an dense and therefore aid the ball in jumping off the bat faster then any other type of wood.
the surface itself is approximately 20% harder and has closer grain than ash. the hardness of maple makes it the least flexible
ash is much more flexible than maple and has a "trampoline" effect when it strikes the ball. instead of jumping off the bat like maple, ash bats have a springboard effect and absorb contact withe the ball. ash bats usually have a bigger sweet spot which gives them a bigger area to make solid contact.