It seems that life is all about shortening concepts into three-letter acronyms (TLAs). Every place I've ever worked, from the military to NASA, just loves to create short, catchy names for technical terms. Ah well.
The current TLA in vogue is "TCO", or "Total Cost of Ownership". The idea is that you take all of the factors involved in something, and you assign a cost in money to them. The one with the lowest TCO rating wins. SQL Server has certainly made a huge gain for companies in this area, because in most situations, our licensing costs are cheaper than platforms that provide the same feature-set and level of support.
But I wonder if a newer measurement is beginning to take hold. There are certainly "free" solutions out there that you can use to store data. And even our higher-priced competitors can take a hit periodically and try to beat us on price. So is SQL Server still the right choice? Well, not everything is a nail, so you don't hit everything with a hammer. If you need a graphics program or a word processor, SQL Server isn't your solution. But for most companies, I still believe that SQL Server wins on a single front: TTS, or "Time To Solution". This means that you can implement SQL Server faster and easier than most any other system. I'm not talking just about the install/upgrade path - most every vendor has now figured out that people only want to click a few buttons for that - I'm talking about being able to plan, test, deploy, implement and maintain a system in your enterprise. We have more options and more help available for that than just about anyone.
The strength comes from the Microsoft franchise. If you've used Microsoft products before, you're used to how we do things. Not that everything in SQL Server is consistent with Microsoft Office, mind you, but by and large if you've used one of our products it is easier to learn SQL Server than another product. Not only that, we put a lot of time into management tools. We don't make you download different packages to manage or code against SQL Server. The "click count" for creating a new database is less than just about anyone else. And we spend a lot of time thinking about making it easier.
So is SQL Server perfect? Well, no. There are always things I want to do to make it better. But is it the right choice for your enterprise? I think in most cases that's true. And we're working every day to make it true all the time.