GNOME3 PPA on the mailing list and my personal opinion is that one should follow the instructions listed with the PPA, namely:
And:Before upgrading your system to a new Ubuntu release (i.e. from Ubuntu 11.10 to 13.04), you should probably run ppa-purge ppa:gnome3-team/gnome3 first.
AFAIK the GNOME 3.8 RC was only released yesterday and final is not due for another week or so, meaning that it's far too young and immature to expect it to be stable=== Ubuntu 13.04 (Raring) ===
GNOME 3.8 that won't make it into the normal Ubuntu 13.04 repositories. Other parts of GNOME 3.8 are available in the https://launchpad.net/~gnome3-team/+...gnome3-staging PPA but beware that many of those components have known regressions from their GNOME 3.6 versions.
I do know that many of the extensions used with 3.6 do not yet work with 3.8, in fact some of the old 3.4 extensions still haven't been properly updated to work with 3.6