Microsoft SQL Server

What I like best with Microsoft SQL Server is that it has some really cool features that put it near the top of its game. For instance, SQL Server internally supports a message queueing system call SQL Server Service Broker. It's a little complex, but it allows you to piggy back a SQL Server license with a transactional queue. Some other features Microsoft SQL offers are things like Business Intelligence, Reporting Services, tabular file storage, and numerous other things.

What I like least about this tool is its licensing. Microsoft tools are expensive. Oracle is also expensive. If you don't need a lot of the stuff offered by Microsoft SQL, you can often use MySQL or PostgreSQL. If you need replication with Microsoft SQL, you'll pay a lot of money. If you want direct language support, MySQL or Oracle (both owned by Oracle) would probably be a better choice. If you want to store and retrieve JSON with Microsoft SQL, you'll need SQL 2016. You can do this with PostgreSQL, without licensing costs and hosting would be cheaper.

If your needs are basic or you don't want to get lost in the open source world, and you want a product that you know it will have support for the next 10 to 20 years, then Microsoft SQL Server may be the right fit for you on your back end needs. My experience was not bad, especially if your internal stakeholders are comfortable with the license costs. This experience is very subjective as the fees varies based on your setup and how much is your expected budget for your project that you want to implement.