Git

Git is far superior at merging than SVN and I think every other VCS from what I've heard. It's also by far the most common so using it is a no brainer. Since it's written by the one true king Linus himself there can be no question to its design and architecture.

The only other VCS tool I've used in production is SVN. In my option Git is a better option for several reasons. Reason one is simplicity, actions like reviewing changes, committing or stashing changes, and managing multiple feature branches is much easier with Git. The second reason I favor Git is the distributed model Git is built around. I can create and finish my own feature branches without needing someone else to manage the central repository for me. Lastly, Git is lightning fast and works cross platform.

The two main alternatives to Git that I know about are Mercurial and Subversion. I've never used either one, but I know a bit about Subversion. From what I remember, Subversion requires a server. I don't anyone using any other source control other than Git, it seems to have pretty much taken over as the primary source control software.

There are not many surviving alternatives for Git (maybe SVN) which in itself is quite meaningful. Git is the best versioning system of all time for programming, period. The difference between a good mathematical tool and sending .zip-s around emailing lists or FTP drives is so high that it's a game-changer.

We were using the TortoiseSVN previously and it was super slow when we created a new branch or switched between branches. Git makes our life easy. :)