Recently I get into situation when I had to run Ubuntu 10.04 LTS on new Sandy Bridge platform. What was my surprise when I realised Canonical "Enterprise" Desktop distro has no support for the new Intel graphical core. There are only community repos without any garante available. In contrary Red Hat Enterprise Linux has got graphic driver update and kernel backports a year ago. From my point of view this is the major failure for Ubuntu as Enterprise desktop. I'm very disappointed with this because a lot of configuration was made considering Ubuntu so called Long Term Support.
upd: Aug 2013
With an update release of the next Ubuntu LTS 12.04.3 the drastic changes were introduced. Kernel version was updated from 3.5 up to 3.8. It's not good at all. Third party vendors usually make drivers for specific kernel. Consequantly no compatibility at all for mission critical enterprise solutions. What is the point of LTS if it's like a new release?