Simon Fraser is Systems Administrator at the Wellcome Trust Sanger Institute, a genomics research charity near Cambridge, UK and the site that did a large portion of the work on the Human Genome Project. Simon writes software for HPC operations in python, and is learning R, Go and Ruby. He also helps run the International Discworld Convention.
What I found hardest about using Git the first time was understanding how to use branches - and I still need more practice using them. I use git in my daily job as a version control system, but in simple ways not for larg collaborative projects.