Joel Christner

Don't get me wrong, PostgreSQL is awesome. It's a LOT more modern than MySQL and has a lot of compelling capabilities.

But, that said, MySQL may be a little bit more beneficial from a learning and career opportunity perspective, not because it's better, but because more people are familiar with it.

Also, with a less modern platform like MySQL you won't get the benefit of some of the things that are built right in PostgreSQL (for instance, having to think through schema design when you really just need to store an array). Having those kinds of mental exercises may make you much more adept at designing scalable/performant schemas, and more importantly, appreciate the capabilities of PostgreSQL.