You can take a fresh install of MacOSX and do anything with Ruby.  Only issue is you need to install some gems using sudo.  Same thing with using system python.  You don&#x27;t need rbenv by any  means.  In fact our designer has no problem getting our rails site running and making styling edits.<p>Hard to say the same with installing Python 3 on MacOSX and getting virtualenv running, which in my experience hasn&#x27;t been so easy.<p>How would you work on a project that uses 3.2, then another that uses the latest features from 3.5, without pyenv?