Visual Studio Team Services versus Team Foundation Server. What is the right one for me?

Lately I’m advising more and more people to start using Visual Studio Team Services or Visual Studio Team Foundation Server. But every I start talking about VSTS or TFS, I get the question what is best suited their projects. But the only correct answer to that question is that it dependents on their wishes and needs. That’s why … More Visual Studio Team Services versus Team Foundation Server. What is the right one for me?