The Mac client has been useful keeping slightly-less-technical team members up to date on our codebase (git on the CLI has a few too many sharp edges for some)

I personally use SmartGit for committing and visualizing projects, and sometimes use Github for Mac if I'm just quickly cloning a repo off of their site.

I use it for importing repositories, and sometimes as a historical diff tool, but usually not for commits. Looking forward to updating.