From the Fugitive Github page:
I'm not going to lie to you; fugitive.vim may very well be the best Git wrapper of all time. Check out these features:
View any blob, tree, commit, or tag in the repository with :Gedit (and :Gsplit, :Gvsplit, :Gtabedit, ...). Edit a file in the index and write to it to stage the changes. Use :Gdiff to bring up the staged version of the file side by side with the working tree version and use Vim's diff handling capabilities to stage a subset of the file's changes.
Quite simply, Fugitive provides a ton of awesome hooks for integrating Vim with Git's best features. Check it out!