I know this might be more appropriate at Ask Different, but as I tried adding tags there, there was no vim tag, only macvim. So I figured I might g
On Yosemite, install vim using brew and the override-system-vi option. This will automatically install vim with the features of the 'huge' vim install.
brew install vim --with-override-system-vi
The output of this command will show you where brew installed vim. In that folder, go down into /bin/vim to actually run vim. This is your command to run vim from any folder:
/usr/local/Cellar/vim/7.4.873/bin/vim
Then alias this command by adding the following line in your .bashrc:
alias vim="/usr/local/Cellar/vim/7.4.873/bin/vim"
EDIT: Brew flag --override-system-vi has been deprecated. Changed for --with-override-system-vi. Source: https://github.com/Shougo/neocomplete.vim/issues/401