There isn't a best. You have your use case, and then you pick the best available for that particular case. Most popular doesn't mean most useful for your need

There isn't a best. You have your use case, and then you pick the best available for that particular case. Most popular doesn't mean most useful for your needs. Do a Google search for one of the many grids available which show which options are best for which cases. If you want to go with something that is best, most popular, easiest to install, etc, then go with MySQL or PostgreSQL.