If you are using Homebrew and want to use the maven formular you have to delete the symbolic link
Thereby you use your homebrew maven installation instead of the shipping version of OSX.
The executable is located at
/usr/local/bin/ which should be part of your path already.
The maven package itself can be found at
/usr/local/Cellar/maven/3.0.3/libexec. This will be interesting for your IDE, which often wants a pointer to your maven home directory. I created a symlink
current so that I can change the version to use at the command line without the need to configure my IDE again.
[/usr/local/Cellar/maven] master@struggy$ sudo ln -s 3.0.3/libexec/ current