Team Foundation Server offers a version control system, but with many more side features, such as bug tracking, user stories, project planning, and it is all integrated into visual studio. Someone put a more complete list of features over here:
Over the past year I have been working with Mercurial and from the moment I typed "hg init" I was in love. My new colleagues are convinced that even though other scm solutions are probably better, TFS provides a better complete package for teams.
What I would like to know is whether it is better to just use TFS, or to go the open source route and select various solutions and integrate them to get a better result, and if its even possible to get that level of integration?
So in summation: Can it be done and is it better to go for various OSS tools?