Personally I prefer crossbows to bows, for almost all situations. I aim for roughly 12-13 strength anyways, just to accommodate the massive 2h weapons I use.
Thanks to the latest patch (which now includes more light/hunting crossbow types) I can use the Masterwork Light Crossbow on horseback. With a decent crossbow skill I can reload on horseback (while moving) almost as fast as an amateur drawn bow, and aim with decent accuracy and penetration.
I don't need to work up to 30 strength just to max out my long range damage, I can spend those points on charisma or intelligence and field a large army. Also, the crossbow can store a single bolt for quick draw firing, not to mention that you can hold the shot for as long as you want.
During sieges the siege crossbow just sweeps the floor. Stand back with all my archers and wreak havoc on the walls. By the time I'm done (3-4 siege attempts) half the garrison is wiped out and there are no archers harassing me when I go over the walls.