I've often used both for different projects, depending on the wrappers provided. Most of the PHP CMS world was all about MySQL first and foremost, which isn't

I've often used both for different projects, depending on the wrappers provided. Most of the PHP CMS world was all about MySQL first and foremost, which isn't a bad thing. But, if you ran into a MySQL limitation, you were pretty much stuck with trying to work around it -- see some of the notes about WP. Moving to an ORM layer or a level (or two) up from direct DB calls can result in more generic SQL and potentially a performance impact.