Terminal ballistics of the two are very, very similar since both occupy a similar cross section area for their projectiles and both are going at speed to which a solid object reacts similarly (eg. not bullets). Older bolts used to be shorter but modern crossbows shoot pretty long bolts.
The major difference between the two in that area would be the weight and speed of the two, with crossbow bolts usually being near the end of heavy-er arrows, around 400-450* grains, but they can be heavier than that. The speed side of things has crossbows at a clear advantage, going in the 400-450 FPS range at the top of the scale when loaded with 400 grain bolts.