Aristotle Pagaltzis has a detailed account of why he chose git has his version control system. My interest in version control systems have improved from being just a dumb user to trying to use it to better the software development process. I have tried some systems, but it was difficult to move away from Subversion because it was easy to set CruiseControl, a Continuous Integration tool, with it.
However, I have started trying out Git recently. I tried out of curiosity to see if Git really managed the changes better. One thing I realized was that Git did make merging and branching really convenient, they were usually considered to be in the domain of administrators and not the developers. As Aristotle illustrates, it is really easy to do the changes without having to spend a lot of time planning what to checkin when. Overall I got a feeling that using Git really helped my productivity.
The main reason for hesitation in using Git is that it is not supported very well on Windows, not surprisingly, since its purpose of creation was to handle Linux kernel projects. I develop mainly using Linux, but there might be others on Windows who I work with. The other reason is to develop a build process that uses Git.
I see the advantages of distributed VCS, in fact that is the reason the other VCS I tried was Bazaar. However it cannot be denied that Git performs quite well, especially when running diffs in the repository trees. It has been a joy to use Git, but I will continue to explore the space for some more time.