Martin Fowler published an informal survey of version control tools among Thoughtworkers. Of course, the big winner is git, and anyone who has been going through the effort of learning it correctly would confirm. BTW, if you want some help convincing people that git is better, do not hesitate to take a look at why git is better than X. On a related note, you might want to listen to FLOSS weekly 111 podcast (direct link here), where CMake lead developer talks about his wonder build tool (I’ll never ever use autoconf again if I need to write some C any day) that is now developed using git.
