A few things... ( apost which somehow vanished!)
1) We now live and global community with global influence, and this applies to our exposure to recordings and to conductors exposure to various orchestras. And a significant number of fabulous players, whether in Bands, German Orchestras, Brass Bands, etc. play BBb. And many play CC. And many Eb. Your conductor, at an audition, will have exposure to many sounds and he/she will make a determination based on whether you fit their favorite sound concept and - of course - mastery of the instrument used.
2) Rick is right to some degree on all his points. I'm sorry, but many former students of mine who stuck to BBb or already owned one were ordered to buy a CC. I know some ordered to play a certain BRAND of CC. Professors have biases, and some towards "my way works, so I'll teach my students THAT".
3) Do some people win auditions based on whether they have the latest "Go-Go Gadget" Tuba? I doubt it. I know one situation when - in a room full of Baers and tuba's worth tens of thousands of dollars, the winner played a 621 Yamaha and an old CC that looked like it lost the Battle of the Bulge. It was German... and no one could have told what it would sound like.
4) No offense to the host, but the assignments under our names are based on... well, I don't know. But to be a member of the forum and "dis" a member because they lack the "professional" status is... well... rude.
5) I'm very privileged to play in one of - if not the - finest band in the country; I pinch myself at the blessing I have to be a part of it, and swell with pride that I could ever be a part of their magnificent recordings and broadcasts. What's in the tuba section? BBb, CC, Eb, CC. Two instruments NOT in CC. Again, those being hired are not being judged as to what key of instrument they are playing.
6) The difference, when it all boils out, is $2K or 2 feet, however you look at it. Why $2K? In the US, the best of the BBb tubas (save for possibly custom Fafners and Rudys) stay in Europe, where the demand is. The CCs come here. If you want quality, especially in the mid-price range, the preponderance of CC tubas are going to be a bit better - in my experience - than their BBb brethren.
7) For whatever reason (a whole new topic), we are 99% started out on a BBb tuba. Usually either on inferior or time-worn (or just plain crappy) BBb axes. We all (I'd wager) by the time we bought our own instrument have a bias to get away from the pieces of $#!+ we used to play... and I think that factors into our decision to jump to CC (or in my case, Eb).

I've used BBb on a number of occasions. I've recorded on them. I've toured with them. I like many of them, especially some earlier instruments built in America with professional intent, including some exceptional instruments with only 3 valves. I'll always have an American BBb in the arsenal... sometimes it's just the sound I want (though the Conn 52J is pretty ^%#$ close).
My $.48 (I already gave 2 cents

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J.c.S.