The only tremendously user visible change is that
multicast dns worked out so well that it's enabled
by default on all interfaces except the default gw.
...
While there has a been a lot else changed 'under the hood', most
of the new-est pieces are still flying in loose formation.
That said, this seems stable enough for day to day use
as a secondary router. I need to write up a bit more
doc on how to do that well.