Not sure if you are talking about a Greddy BPV venting to the atmo and causing damage to the car/bpv or if you are talking BOV on the f2t in general, however to sum it up for u
Advantages: sounds cool
Disadvantages: Rich shifts
basicly u just have to weigh up your options. For me my idle is fine, rich shifts dont bother me too much and i get little to no backfiring once i "tuned" my BOV. I like the sound of it, in my oppinion im allowed to be a lil bit rice seen as my car is actually turbo, if i was total rice id have gotten an F2 powered car with an electronic supercharger and a fake bov sound on my stereo.
Basicly its up to u.