Another good way to see the different between 2 branches

git difftool --help
...
-t <tool>, --tool=<tool>
Use the diff tool specified by <tool>. Valid diff tools are: araxis, bc3, deltawalker, diffuse, emerge, ecmerge, gvimdiff, kdiff3, kompare, meld, opendiff, p4merge, tkdiff,
vimdiff and xxdiff.
...

@dexterous which one is your favorite?

@swarut i'm a vim guy, so it's mostly vimdiff/gvimdiff. But I end up using git-difftool very sparingly as vim-fugitive fills that use case much better. :)