I like SQL Server as a database. I think it's very complete, solves most of my problems, and is easy to use in work. It costs money, but less than some others. It's also more complete to me than some of the open source databases out there. That being said, I think most of the top five or six relational platforms would work for me and I wouldn't hesitate to use them.
I ran across a post from Steinar Gunderson, who worked at Oracle on the MySQL team. It's on his last day there, and it's a bit of a why did he leave. I like that he notes he found a better opportunity, but he digs in deeper. Why did he look for a new opportunity?
The answer seems to be that MySQL was a shockingly primitive piece of software, according to him. He felt there was lots of room for improvement and change, but people seem to like and accept what MySQL is and does. He is proud of what he has done, but felt that this was a product that was vastly inferior to other database platforms.
That's interesting, because I think MySQL works fine and is in use in many situations. While there might be plenty of things that can be improved, I'm a practical guy. If the technology meets my needs, and those I can foresee, I see no reason to change. That being said, I wouldn't reach for MySQL to start a project. If it wasn't SQL Server, I'd lean towards PostgreSQL.
There are a couple of examples in the post, and it's certainly a good post to write on your last day. If you published it when it wasn't your last day, it might quickly move in that direction.
If you use MySQL, I'm curious what you think. If you don't, would you if SQL Server weren't available? Would you learn MySQL for a new job? Or are you a die-hard, this is my platform kind of person?