We have used MariaDB since SkySQL was founded (powering our support system, website, wiki, and so on), but this news was timely for me because I recently observed that MariaDB adoption among our support customers at SkySQL has tripled over the course of the past year.
The reasons are as varied as one might expect. MariaDB performs better for some; the wider array of included storage engines makes it more suitable for others; the developers are (unsurprisingly) significantly more in tune with the principles of Free and Open Source Software than Oracle; some would simply rather not rely on Oracle.
And, of course, I like to think that SkySQL's close partnership with MontyProgram also helps make MariaDB an increasingly viable replacement for MySQL among businesses with critical support needs for their databases.
In any case, congratulations to the MariaDB team. Fedora's decision underscores not only the health of the "MySQL Ecosystem" in general, but the validity of Monty's approach with MariaDB.