While I've seen many projects out there use Oracle DB without that many issues, I'm inclined to say that MySQL/MariaDB and PostgreSQL are both easier to work with due to how easy it is to setup new instances (either on a server, or in containers for testing/development) and how they're generally just simpler to use and more carefree products (though perhaps that's because of sane defaults, e.g. no problems with tablespaces that don't autoextend), even when something like Oracle XE exists.

On a more humorous/worrying note, there's also this: https://news.ycombinator.com/item?id=18442941