@Lucasta. I agree this is a nice bow, but I'd call it more a Staurobow upgrade, not an O-bow upgrade. This has just +2 r.att more, and while the +4 agi is nice (and mnd too for holy bolts like you said), its a massive -13dmg compared to O-bow (thats a 25% drop!). On WS this WILL hurt you.
RNG's, if you have an Obow, stick with that.
THF's, if you have a Staurbow, get this.