well, packages for OSX may include packages for python.
pip is a packager for the python world – you should only ever be able to install python-things with it; homebrew is a package manager targetted at OSX; it doesn’t impose any restrictions onto what software you can install with it – since python is a subset of software.
installing things with brew will install them into /usr/local/;
installing things with pip will fetch packages from the Python Package Index, and it will install them in a place where your python interpreter will find them: either into your home directory (e.g. ~/.local/lib/python2.7/site-packages/) or in some global search-path of your python interpreter (e.g. /usr/local/lib/python2.7/dist-packages/)
if you have installed the python interpreter via brew, then chances are high that any python-package installed via brew will be usable out of the box.