I like brew installing `emacs-mac`[0] which installs a port run by a developer in Japan. My favorite feature of it (among other amazing osx specific changes) is the sub-pixel scrolling support in emacs.
When you setup your `init.el` you can call `(package-install x)` and if the package is already installed it'll do nothing but just make sure it's there.
If you wanted the whole thing figured out ahead of time I recommend using Spacemacs[1]
I ported over a few years of custom keybindings and other config to Spacemacs. It was not too difficult, basically you can just tell Spacemacs to load whatever.el at startup.
Eventually I switched to evil-mode and I rarely use most of my old keybindings, but I still keep them around!
When you setup your `init.el` you can call `(package-install x)` and if the package is already installed it'll do nothing but just make sure it's there.
If you wanted the whole thing figured out ahead of time I recommend using Spacemacs[1]
[0]: https://github.com/railwaycat/homebrew-emacsmacport [1]: http://spacemacs.org