In upgrading to the new ThinkPad X1 Carbon Broadwell ultrabook, I'm debating whether to switch back to Fedora after having used Ubuntu for a number of years on my main production system after some falling out with a few less then stellar Fedora Core releases back in the day (of course, on test systems, there's plenty of Fedora around here but this is just about deciding on my next main OS for business tasks). In waiting for the new Broadwell ultrabook, I've been running some fresh Ubuntu and Fedora Linux tests on some other laptops/ultrabooks in the office.
The adoption of systemd in Debian has caused quite a ruckus, but it has other ramifications. For example, Ubuntu will soon use systemd by default, most likely in Ubuntu 15.04. The community has put together a great wiki page that explains the differences between upstart and systemd and how you use it right now.