Found here.
Interestingly, there's a fairly long "Known Issues" section. It's disappointing how many issues there are, but at the same time, the listing here is very helpful. It's good to know that certain hardware is known not to work so that I don't spend all my time trying to debug it.
It's kinda sad that all these different distros need to develop their own testing methodologies. It seems like one area where the open source model could really work. Everyone co-develops a comprehensive test suite, which would then lower costs for OEMs and actually let them concentrate on delivering better hardware.
Too bad you can't get the distros to agree on anything.