I think the extensibility is huge for emacs. It's very easy to do and very powerful.
But here's the really cool thing: I barely know any Lisp. The most I've extended emacs is adding key bindings. But I haven't been compelled to learn enough Lisp to add some awesome feature yet.
It's so easy to extend that most users never need to. Google has yielded every language mode and feature I've ever really wanted. I'm sure I'll start hacking on it sometime, but there's already so much out there that I have an emacs much better than emacs out of the box without having written more than 2 lines of what's in my .emacs and my .emacs.d/
An oldie but a goodie, both the post and the issue. IDE editors suck. Emacs as an IDE sucks. Somebody needs to get us out of this mess :-( Since I don't think emacs will ever be a decent IDE, I think the day will come when somebody writes a good programmer's editor that is designed for embedding in an IDE. Then people can build their everything-and-the-kitchen-sink IDEs around it, and programmers can use the same editor to edit source files in their IDE that they use for editing text files in their terminal sessions.
But here's the really cool thing: I barely know any Lisp. The most I've extended emacs is adding key bindings. But I haven't been compelled to learn enough Lisp to add some awesome feature yet.
It's so easy to extend that most users never need to. Google has yielded every language mode and feature I've ever really wanted. I'm sure I'll start hacking on it sometime, but there's already so much out there that I have an emacs much better than emacs out of the box without having written more than 2 lines of what's in my .emacs and my .emacs.d/