This is pretty much the only reason I've been waiting for 16.04 – to get rid of upstart scripts and standardize on systemd. Still going to wait for a couple months while people iron out initial bugs but definitely excited about this release.
There's going to be a 16.04.1 release just 3 months away from the initial LTS release; I believe it is just for that.
https://wiki.ubuntu.com/TrustyTahr/ReleaseSchedule - this schedule is for 14.04, but I believe it's been the same for quite a few years already.