We’ve been using GNU/Linux platforms since early Redhat and Slackware distributions in the mid-1990s and have currently settled on using Ubuntu (either server or desktops) unless a product is based around a different distribution e.g. CentOS.
As we support these ourselves then we rely on our own skills but more importantly the community support. Ubuntu inherits the strong community of all the Debian distributions and so has a robust foundation on which we can build our own support framework without resorting to outsourcing contracts.
We leave the upgrades late. This is for the same reason for leaving Microsoft Windows upgrades until at least SP1 is available, and that is that the early adopters should have reported the vast majority of the bugs and more importantly the fixes will be available.
10.10 > 11.04 upgrade
We avoid using Unity for regular desktops and so use the legacy GNOME desktop. So far on diverse systems we have only had to turn off one setting in System-> Preferences ->CompizConfig Settings Manager under the General then OpenGL we have unchecked Sync to VBlank. If you don’t have this package then it is compizconfig-settings-manager
We did this because when playing videos (Media Player or VLC) and similar Window operations then it seemed jumpy.