The builtin OpenSCAD editor... meh. Put the OpenSCAD window on your second monitor, hide that ugly code editor, and turn on Automatic Reload and Compile so you can enjoy programming bliss in TextMate with color coding and lots of tab triggered code snippets.
Look around the bundle, there's some handy stuff in there. Select some code and press Ctrl + or open a script with a ton of modules and click cmd+shift+T and be amazed that you lived without it this long.
cd ~/Library/Application\ Support/TextMate/Bundles
git clone git://github.com/tbuser/openscad.tmbundle.git OpenSCAD.tmbundle