My use case can pretty well be summed up as "things an ORM can do for you out of the box." As a developer living in the shallow end of the RDBMS pool, switching a hobby project over is a matter of hours. If your usage is similar, learning it well enough to get by could just be a matter of:
apt-get install postgresCompared to MySQL, the presence of schemas is a big win for me (same as 'user' in Oracle). Also, I can't move away from Postgres because it's the only DBMS which supports transactional DDL, which the ability to roll back an "add column" as part of a transaction.
http://stackoverflow.com/questions/2901453/sql-standard-to-e...
To really go out on a limb, I would posit that MySQL's view on RDBMS functionality influences its use, which I bet does not square with more traditional systems. Anytime one finds a shift in world view, the code becomes hard to rewrite and still behave the same way.