Fedora's change to MariaDB looks to be more certain than openSUSE's (SUSE's community Linux) potential move. In Fedora's case, the shift is being suggested by Jaroslav Reznik, Red Hat's Fedora project manager, and there seems to be no opposition.
In addition, he said that while he's not "unhappy with Oracle's MySQL...but I believe that new default will bring some more goodies to our users without any unpleasant side effects. And as we believe in choice, you can still choose Oracle's MySQL over MariaDB."
Fedora's developers, however, want to not only make MariaDB the default DBMS, but to stop shipping MySQL with their distribution. Of course, you would still be able to download and install MySQL on Fedora.
The openSUSE community isn't as sold on this changeover as the Fedora programmers. A few openSUSE developers have objected to the proposal. In particular, several think there's not enough time left to make MariaDB the default DBMS in openSUSE 12.3. After all, openSUSE 12.3 just went into its first and only beta. Personally, I don't see MariaDB becoming the default in openSUSE 12.3 by its March delivery date.
That said, I'll be watching developments here very closely. If the snowflake of Fedora, and thus eventually Red Hat Enterprise Linux (RHEL), switching to MariaDB falls into place, I can see an avalanche of other Linux distributions moving away from Oracle's MySQL to MariaDB. That will change everything about Linux DBMS and that, in turn, will transform the Web server, data-center, and enterprise application worlds. We are living in interesting times.