Mac Text editors

Have you looked at aquamacs? (emacs for the mac).
its at aquamacs.org.

Seconded, especially if you also want AUC-TeX features. For pure R purposes, as others have noted, the built-in editors in R.app and Rstudio are often good enough and less confusing to students during teaching. 

(I gather that .emacs functionality ends up in ~/Library/Preferences/Aquamacs\ Emacs/* . You're not really expected to bypass the menus, though.)

-Peter D.

Peter Dalgaard, Professor
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com