I have O.Bow and Selene's. I have 8/8 on Archery because of sam/rng but if I didn't enjoy soloing Snoll in 18~ seconds for people, I would drop Archery merits and put them in Marksmanship and just main O.Bow.
As mentioned; the damage is respectable and Trueflight is a cool WS.
I went 1/2 on O.Bow. Takes 12~ hours to pop Wyvernpoacher and he's a lottery spawn but you can easily read up on that on wiki so I won't waste thread space on it.
The ONLY weapon I bothered spending 2m+ for was my Blau and I'm even considering dumping that since there is better out there.
Some people like their fruit a little riper, others like their fruit with a bit more crunch. It's all personal preferance.
Another factor to consider is that if you're RNG, there are going to be other people working with you and while you might be A1 elite, they might suck all sorts of *** and their gear could follow suit. That drops the overall efficiency of your PT/Alliance by like 50% (just for argument's sake - not to be considered an actual percentage), and nullifies all the work you put into your rng. Not to mention, if they suck and you eat dirt, all that gear you have is doing 100% nothing.
I reitterate; Reraise is a paramount concern or at least should be, of everyone and anyone that does anything in Final Fantasy. FF9 they call it "Auto-Life" lol
Edit:
I forgot to mention another favorite benefit of O.Bow vs. S/E/V.bow & Fay Gendawa - status bolts. I'm sure that needs nothing more than casual mention as everyone already understands their purpose.
Simply setup a few macros with /equip ammo "Status bolt here" /ra <t> and slap the macro if you should need some Bloody bolts etc.