$ git --version
git version 2.3.2 (Apple Git-55)
$ which git/usr/local/bin/git
After the brew install
brew install git
...
$ git --version
git version 2.2.0
$ which git
/usr/local/Cellar/git/2.2.0//bin/git
it seems that the version of Brew is older, so I advise staying with Apple (Developer's Tools).