Only major difference from Release Candidate 1 is that it now provides visible feedback that Gnusto is handling the download when you click on a link to a z-code file.
marnanel's been testing RC1 on the Mac and it looks like the handling of incorrectly MIME-typed files may be more challenging on that platform. Some digging in Bugzilla seems to point towards it being OS-specific. Works fine on Windows, though. I suspect it works fine on Linux as well, but am still awaiting confirmation.
edit: Here's a more proper link: Gnusto 0.8 Release Candidate 2