not heard the Carbon. back in 2011-2012 i did own the BHSE and 009's for a while. i enjoyed the BHSE and the Aristaeus too. it's not fair for me to use my now 9 year old memory for a compare. but if i had to say, i think that the MSB Select is far ahead of the BHSE. more transparent, more dynamic, more clarity in the mids, unlimited sense of power, serves the music and never a false step. this is more comparing my speaker system (link to my audiogon system below) to the MSB Select compared to how i thought the BHSE compared to my speaker system back then.
the MSB Select has a list price x6 of the BHSE; so it better be better. although that does not always really figure into things.
that said; the BHSE/009 combo was sweet and an end game set-up. one to aspire to. i will always recall it in a very positive light.