Before I used an Apple machine with OSX, XEmacs was my editor of choice. Recently I saw Emacs 23 being released with native OSX support in the main repository (well, NextStep support formally, but with Cocoa bindings, which makes it OSX native I guess).
That alone was enough to revisit the old friend. With caution, because I still feel the pain somewhat of switching to TextMate *from* Xemacs. Another reason is that I sort of lost patience lately with proprietary applications. (TextMate in this case). I’m finding it less doable to have to wait for another developer to be able to find the time to fix issues or provide upgrades within reasonable intervals.
I’ve had a similar experience with Ecto not that long ago. You’d think I’d have learned by now…
Using Emacs again instead of TextMate was actually quite easy. My fingers still ‘remembered’ the keys to press apparently. However, the learning curve to use the editor effectively is still steep. It’s still, and now more than it was with the native build, a joy to work with though.
What keeps (re-)surprising me about Emacs is that there’s apparently a mode or package for anything you want to do to get you 80% of the way and, thanks to the strong customization, the other 20% is around the corner.
I switched last week and since then I’ve discovered a mode that lets me view PDF-files (docview), a mode that connects to my microblog (identica-mode), spent quite a few hours in org-mode organizing my notes and task-lists (including syncing them to my iPhone), editting XML files in nxml-mode and blogging right now with the weblogger package.
I seriously think you can take a bare iron machine, install a minimal linux kernel on it, configure Emacs as the ‘sole interactive application’ on it and still end up with a useful machine, not missing out on any task you’d want to perform.