If we stick with Debian, we'll find ourselves back in this situation fairly soon, since Debian's security team only supports oldstable for one year after a new stable is released (approximately — there isn't a set timeline available).
Ubuntu LTS releases, on the other hand, give us predictability and five years of support. That makes me very happy from an infrastructure standpoint. And the more up-to-date packages in Ubuntu repos make our feature devs happier, versus having to maintain backports for modern software.