How it differs from magit or fugitive except price? I've tried magit and fugitive for some time, but as for me, adding this plugins to workflow just complicates tasks related to VCS. At the time of this writing, whichever editor/IDE I use, my VCS stay in command line.
It is a little bit of a weird bastard child of the ideas in magit and fugitive, coming from vim and fugitive myself, but having always admired the workflow of magit. Mix that with whatever is possible interface-wise in Sublime Text, and you have SublimeGit.
I think it depends a lot on your workflow. If you're comfortable with, and used to, the command line this might not be for you. But for easy staging and committing of individual files/hunks I find it very useful. Also, even if you're just using Sublime Text as your commit message editor, this will give you color highlighting of you commit message, including gently nudging you towards good practices for commit messages.
I have tried plenty of GUI clients, but I am the fastest with git in the command-line hands down. git has quite a good user interface for command line use with its hunk-based staging, drop to $EDITOR to quickly edit a diff, etc.
Also, there is completion for git in shells such as bash and zsh.
