crushed dsm - ghetto
greddy type rs/type s - suck
synapse synchronic - hype/shitty mounting design/stays open at idle without anti-stall fitting.
hks ssqv - works excellent (kinda annoying with the chirpy shit but you can take the fin out)
tial q - expensive, quiet, works decent
Turbo XS - decent
Freddy - see Greddy

That's about all of the one's I've had experience with. You basically want a bov that will stay shut on idle. Many of the bov's on the market are "push type" and only provide all or nothing purge. Any way you look at it re-circulating is ALWAYS better than atmospheric purge on a maf equipped car. I'm going to attach a duck call to my ssqv one of the days.