I should add some more related links:
Debian making NTP happen by default too is being discussed in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731594. openntpd was
suggested, but this effort seems to have languished, and in Ubuntu we
have ntp in main, not openntpd.
An ntpdate issue in both Ubuntu
(https://bugs.launchpad.net/maas/+bug/1257082) and Debian
(https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731352) remains
unresolved, but I think this goes away when ntp is installed, which we
want to do on a server anyway. Assuming we don't want this on a desktop,
it would still be nice to fix this bug, but it has languished in Debian
a little because ntpdate is considered deprecated by its maintainer.