While there are bugs in the now current linux code, there are some big
names that trashed mbufs. Van Jacobson has a BSD based stack that
he's heavily hacked to *NOT* use mbufs, but a scheme that escapes me
at the moment. He also did the hyperoptimizations of the checksum
calculations for the m68k (I believe).
Why do people like them? mbufs are good enough to get decent
performance on most available hardware and they are in a stack that is
relatively solid. The linux crowd knows well the pitfalls of trying
to reinvent the TCP wheel :-).
Warner