i have both, and prefer the vintage,
the vintage can get quite clanky and aggressive, but i never hear any samples showing that side of it, i use it for a clanky aggressive p bass tone at the moment and its always on.
i'd say the b3k is more 'precise' and metallic, and you can coax some insane attack out of it. neither pedals kill your low end either, very full sounding.
if you're anywhere near leeds, then you're welcome to come try them out.