[Vasu]

Well, xBows will always out-DPS a bow (talking about NPC stuff here) except if you're pure STR. Look at it this way. When you enhance a bow, the dmg added is proportionate to the base dmg. BUT when you add STR, the dmg added is an absolute value, not a %. As you gain levels, slowly, the effect of STR kicks in, and bows start out-DPSing xBows. So I'll say lvls 20-40 xBows, and for the lvl 40 weapon and above, start using bows if you're pure STR or 25 SPR remaining STR.