The Git support done by Microsoft in Visual Studio is just good enough for basic work (commit/fetch/merge and push). My advice is just to avoid it...
I highly prefer GitExtensions (or in less proportion SourceTree). Because seeing the DAG is for me really important to understand how Git works. And you are a lot more aware of what the other contributors to your project have done!
In Visual Studio, you can't quickly see the diff between files or commit, nor (add to the index) and commit only part of modifications. Browse your history is not good either... All that ending in a painful experience!
And, for example, GitExtensions is bundled with interesting plugins: background fetch, GitFlow,... and now, continuous integration!
For the users of Visual Studio 2015, Git is taking shape if you install the GitHub extension. But an external tool is still better ;-)
