I use Terminal-based Emacs exclusively. Couldn't stand all the "distractions" (bells and whistles) of Aquamacs. But, more importantly, with this mode I can use Emacs everywhere, including my servers over ssh, with exactly the same setup.
I bind Option to Meta in Terminal.app and that works very well.
I agree with Terminal emacs being available anywhere. I do miss the anti-aliased fonts that are available in Emacs.app, but I have to be able to start separate emacs processes for different projects.
Also instead of using cmd-c and cmd-v Mac key bindings, I do M-| (shell-command-on-region) to 'pbcopy' to copy the region to the OSX clipboard. It's a godsend.
I bind Option to Meta in Terminal.app and that works very well.