I’ve been using SPE as my Python editor for a couple of years. It takes an IDE approach to the user window and UX model. I liked it, and I even donated money to its support fund.
But I’ve been an Emacs guy since back in the day. I was never fond of Emacs’ Windows integration, so I fell out of the habit of using it during my Windows years.
I’ve now discovered Aquamacs. Baby, I’m home.
Seek Nuance 
I’ve found this carbon emacs package (http://homepage.mac.com/zenitani/emacs-e.html) to be more stable and noticeably faster than the aquamacs. It’s even nearly as pretty (and osx-ish).
@redochre: I tried carbon emacs before finding Aquamacs. I can’t tell you why I liked Aquamacs better, but I did…
I’m not saying carbon emacs is bad — just that I liked the feel of Aquamacs better.
I occasionally read complaints about Aquamacs’ default behavior of opening files in a new window. But it’s trivial to change its behavior to the Emacs standard of reusing the current window, with an Aquamacs customization variable.