You can load crossbows with blinding speed and even fire them in melee with little fear of reprisal. There is a 3rd party feat from Paizo that allows you to apply a lot of feats to a crossbow that would otherwise apply only to bows.
The Great (?) Crossbow from RoS is pretty nice, and the Gnomish Crossbow Sight from A&E is also pretty good.
Crossbows are generally very inferior to (composite) longbows, but a fairly heavy investment in feats and items can make them worthwhile.