On the terminal I find `ydiff -s --wrap --width=0` very good for a comprehensible side-by-side diff: https://github.com/ymattw/ydiff

I definded this wrapper script ~/bin/git-ydiff-s:

    #!/bin/sh
    git diff "$@" | ydiff -s --wrap --width=0

with which you can do `git ydiff-s` in your repos easily.