Having an older AMD card that works with the r600 mesa driver is not that bad, the performance is quite decent lately and it always supports the latest kernel and xorg.
But indeed, AMD screwed up the release of the 7000 series even on Windows.
A little afraid to try it, my system is mostly functional with either 11.06 or 11.11, and subtly or not so subtly broken with any other revision. I suspect 12.04 will be the next driver worth upgrading to. Looks like the AMD driver cycle is an improved driver, followed by a horribly broken one, followed by 3 months of no forward progress.
Ah well, Kepler should be announced on March 12 or thereabouts. I'm also done with AMD, going 100% green for all my hardware. I'll give AMD hardware another spin in a year or two, I'm too stupid to learn from my (or others) mistakes.