Earlier quoted context omitted.
MySQL is possibly the single hardest database to port to/from, because it supports nothing .
In that case porting FROM it should be simple. TO it would be hard if you're using all those fancy features of your current DB. That's why I eschew all the sirens from Oracle DBA's of "oh... but Oracle can do that too!" Keep database activities in the database and application activities in the app.
Postgres, Oracle, MS SQL all support a (very large) common subset of features, so if you avoid stored procedures and db-specific features, you can port among them easily. This is not true for MySQL.