I've used MySQL over the years and it has served me well. I didn't know the default behaviour is a bit messed up. Look at this video for some examples:

Because there's a lot of validation being done by the php-applications  I work on, I've yet to run into the problems described above.Though the default configuration has some problems I'm not migrating my current projects from MySQL to something else. But for fresh new projects, I'll consider using PostgreSQL.

If you are considering this as well here's a guide by Chris Fidao (I stumbled upon the video above when reading that guide). If you are in any way interested in running your own server you have to subscribe to his excellent newsletter, Servers for Hackers, and buy the book with the same name.