--- You wrote:
What are the benefits of BeOS about the AUDIO in comparison with the other OS?
--- end of quote ---

well this is based on my recent experience transitioning from mac programming
to beOS programming:

-Be is selling itself as the "mediaOS"
(http://www.be.com/products/beos_tour/screen3.html)

-you can get real-time sound in/out with about 10 lines of code instead of
1000's (as in mac) thats enough reason right there for me.

-more on user level: the multi-threaded audio/midi/? streams let applications
easily pass audio and control messages -- latest BeOS versions let you "mix" all
currently running sound apps, and ive heard rumors of having an "effects"
stream, so (to use
current commercial metaphors) you can have a bunch of running sound applications
all patched into eachother, essentially each app becomes a "plug-in" to the OS's
sound
manager. 

-on top of that, BeOS is just a simple, elegant OS (no legacy code garbage) that
runs on
PPCs(except G3s) and Intel boxes , and is not Microsoft or Apple.

- since we as csound users are used to being marginalized anyway, i would
encourage
everyone to check it out and consider Be-ing

--- im really trying to move in that direction  for all my "personal" projects