Whichever one you prefer the sound of and suits your listening environment best.
I'd say the BX2 would give you deeper bass and greater scale, while the CM1 would be more refined. It may also depend on the equipment you are partnering it with.
Agreed. Only YOUR ears can decide. If possible demo them both and decide for yourself. Bring your amp with your to store if they don't carry what you have. Or buy both online and return the ones you like less. I haven't heard the BX2s but literally listened to the CM1s this week and was thoroughly impressed... so much so that I nearly bought them on the spot after spending months contemplating/researching my first HiFi stereo setup.