Hi John,
Sorry, I accidentally deleted your original e-mail and thus am breaking
threading; my apologies for that.
As a matter of fact, I wrote an article recently to address the very
questions you ask:
http://www.evaristesys.com/blog/kamailio-as-an-sbc-five-years-on/
As always, it is a matter of professional opinion, and I do not speak
for the project nor the intentions of the core developers.
-- Alex