You can use other emacs builds on mac OS. I use Carbon Emacs. Emacs 23 has a native cocoa build now.
I found the Emacs Starter Kit (http://github.com/technomancy/emacs-starter-kit/tree/master) and the Meet Emacs Peepcode Screencast (http://peepcode.com/products/meet-emacs) to be awesome. After a couple hours of working through the screencast, I was a 5x better Emacs user than I had been after 2+ years of Aquamacs use. You have to "get" Emacs and Aquamacs doesn't force you to do that. The $9 for the Peepcode screencast was the best money I've spent in a long time.
http://atomized.org/2009/08/cocoa-emacs-231-cvs-builds-and-t...
I've since reverted to the Carbon Emacs 22 build (since I can't cope without fullscreen).