As we find packages that do not work, they are tagged as such and removed from the list.
Lots of packages do work (Dashboard, blinkled, many others) but some do not.
I have been working on Avahi. The install process crashes the whole box. After a reboot it seems to work though.
If you encounter a package that doesn't work, it might be wise to open a ticket in redmine and report it.
That's what the prerelease/RC stage is all about... shaking out these bugs