Despite chatter about structural similarities between the two, I prefer Chaos to BC. Chaos has always struck me as a green scent, and BC a chypre-oriental incensey hybrid. When BC behaves (which is to say when it delivers a nutmeg accord), it's stellar. When it doesn't, it's cold and annoying. Something prevents it from fully developing on my skin, most of the time.
Chaos, on the other hand, has this wonderfully peculiar "milky pod" note to it, smack in the middle, that hints of midsummer's tangle of vegetation--and what is the proper name for that milky pod?
Honestly, they aren't six of one, half dozen of another. To me they aren't that similar.
Sonoma Scent has a wonderful dupe of Chaos at an unbelievable low price. It's one of her bestsellers and rightly so. No need to pay $150.00 for a partially full bottle, unless one is a purist.