first one is just personal opinion, bms rely heavily on hurricane, but xbowmens are more diverse, requires more micro (i guess) their skills are just built to kill mobs, (piercing arrow, frostprey, that freeze skill, etc etc) therefore their skill is aoe based, whereas bms focus on a single target.
first job: equal. second job: bow > xbow. third job: xbow > bow. early fourth job: (with snipe 30)xbow > bow > xbow(no snipe 30). late 4th job: bow > xbow. Who cares, they're only used for se anyway. If you want dps play an nl or sair. If you don't care for the monotonous grind that is 120+ though, I find sniper to be a lot of fun, with relatively strategic gameplay (about as strategic in you're going to get in this casualfest of a game anyway).
BM's have the third best dps in game. They aren't far behind NLs at all. As far as xbow vs BM in this server at the moment before new source, bm will out dps a marksman at a single target mob, but mm grind faster. Snipe is a 10 second cooldown in this source so its better than the usual 15 seconds in v62 but still not quite enough to make up for the decreased damage strafe does (which is your end game attack[100% dmg]). Piercing arrow isn't very useful until the charge up gets reduced to 1 second in new source, even though it can hit very hard (850%dmg). Still though, I find strafing/sniping better dps at bosses obviously (and grinding as well atm) but I haven't grinded much since 14x so thats not that big of a problem. As for BMs: Hurricane does a bit more dps at the moment on single targets like krex/ht. Strafe is a bit slower and 10 second snipe doesn't quite make up the dps gap. 5 second snipe will balance the classes out I believe, and strafe will possibly freeze mobs as well (not confirmed yet). Another pro for xbow is the weapons and scrolls are much, much cheaper so its easier to scroll an endgame weapon yourself without having another character to fund it. Frostprey is a great skill as well for grinding, freezes mobs and since mm are a bit slow it helps you keep your distance.