Just Ubuntu though admittedly I use a lot more packages than average so there's more that can break across updates. Also a lot of things that have caused me problems over the years are getting more stable.
Ubuntu is famous for breaking spectacularly as soon as you start install PPAs or non-stock packages. I'm still convinced that APT is not the right tool for a desktop OS, it's way too complex and has too much automagic to withstand a user that wants stuff like the latest versions of GCC, etc.