I agree with JosBurke.
I too have both the CF and CB lenses and can see no difference between the two, EVEN when enlarging the photos. In fact, I have sold my CF lens because I have gotten so used to the CB and don't see the reason for holding on to both. However, if anyone is in doubt or second-guesses the CB vs CF factor,then by all means choose the one you feel you should. I have been shooting for more than 30 years and in many countries and conditions and I always carry the CB with me ( along with one or two other lenses). It is very nice to see people so interested in their equipment and how to improve their image quality. Keep it up.