When B-News was 4 months old, its creator was contacted by someone who's name will not be disclosed here (just let it be said that it was not Jürgen Helbling), who suggested another encoding method based on 'quoted printable' escaping of control characters. A few tests were done, but B-News didn't adopt that method because its development had gone too far in another direction already, and for other reasons that will become clear in the next two paragraphs.
A few months later, in another part of the usenet world, the first work started on a "standard specification" that was based on that same method, slightly extended, and now it had also got a name: yEnc. You'll find the name of B-News' creator in the credits list on the general topics page on the yEnc site, even though he didn't do more than follow the initial discussions about it.
yEnc is less CPU-intensive than B-News and reaches about the same low level of overhead, but it doesn't avoid the use of all control codes, it just leaves out those that were (experimentally) observed to have undesired effects on some servers, which means that it's somewhat less RFC compliant than B-News.
B-News was designed to be as compliant to RFC's as possible (except for assuming 8 bit cleanness) to avoid any problems with existing news software, yEnc was designed with an attitude of "if it doesn't follow the RFC's, then they'll have to change the RFC's."
The reason of yEnc's success is that it was heavily plugged in newsgroups and with newsreader writers right from the start, something the author of B-News wanted to avoid until it had proven to work and had been tested on a broader basis (including mail).
On the server where it was born (telenet's), B-News has in the mean time grown to be the primary posting method. That server used to keep all binaries local to save on feed bandwidth until that was changed recently - to the discontentment of some usenet users who now start finding BN posts in "their" groups without knowing what they are.
Because of the huge success of yEnc and because it's useless to invent the wheel twice, development on B-News has come to a virtual standstill. It is expected that telenet's users will gradually move towards using yEnc over time: as it is now, some are heavily opposed and others say it's a dumb thing not to move right away, the kind of discussions that can be expected on usenet ;-)