So I also use MYSQL, the main consern for me as most of the others who use it are security issues, but I'm guessing that if you like it cause is faster in biger servers, then you could; deny from all and allow only from local host most of the folders, right? and then you would be protected against sql injection... and be safe as if you where using sql, wouldn't it?
The one thing I hate of mysql is "xampp" (I know there are many other programs out there, but talking about xampp right now..xD) you need to adjust and tune it if not as your server gets more people you will have query failiures... besides that I thinks is nice, but I think im going to try out Postgresql for a change, heard some good things about it.