Carbon vs. Aqua vs. Cocoa Emacs builds
There seem to be a few camps when it comes to Emacs on OSX; Carbon versus Aqua Emacs. It seems the argument is that Aqua is a bit too far from standard Emacs and if you get too comfortable then you will have trouble using any other build of Emacs.
As a developer who has been trying to get into Emacs for a few months now, I have been using Carbon Emacs with the Emacs Starting Kit and things are going OK.
But with a Cocoa build of Emacs coming with Emacs 23 (and nightly builds), will this change anything?
Should I consider using the nightly Cocoa builds in anticipation? I'm very curious to find out the benefits and if there will be significant changes or improvements over the two main OSX Emacs apps.
Answer
As a long-time emacs user, I would recommand against "exotic" versions of emacs (aquamacs falls in this catagory, but this "starter kit" thing as well, and let me try to explain why), just for the sake of finger-training and brain-training also.
My argument is that you want to learn emacs once and for all, regardless of the platform (i.e. combination of OS/desktop/hardware/whatever) you'll be using emacs on. Almost every flavour of unix comes with a preinstalled emacs, so the hope is that you'll never have to resort to e.g. vi, even in the most hostile environments (for instance, editing a /etc config file on a remote HP/UX server via ssh). You'll still be able to use the old emacs 19 that sits there, and even if it does not have your config files (that is, your starter kit, your keybindings, and stuff), you'll still have say 70% of your usual editing powers at hand.
And if you find yourself often forced to edit those file on that hostile machine, you will want to mirror your .emacs config on that old emacs as much as possible. Of course, you will lose along the way some stuff that is not supported there, but again, good'ol emacs will always be emacs even if a diminished one.
Of course, if you control perfectly your working environment, e.g. if you only ever work only on your shiny mac laptop, you might want a fancier version of emacs, just because it will be easier to use Cmd-C/Cmd-V than to learn Meta-W/Ctrl-Y. And for the same reason if you develop in one language you might want to actually use a full-blown IDE with super-powers tailored for that language (e.g. Eclipse, Xcode, whatever). But you know that sometime, you will have to edit an unexpected file like a shell script, or a web page, or a Python script, or who knows what kind of text file, and this is why you want to use the omni-powerful One True Editor in the first place.
And this is the reason why I use Carbon Emacs on my shiny mac laptop: I get the exact same (emacs) features on the Ubuntu box I'm forced to use at work, using the exact same config files (handcrafted during my ten years of emacsery), and still I can feel quite confortable on other people's or other machines' emacsen.
...my two cents