Some people consider Emacs to be not merely a text editor but almost a complete operating system. Some users find that they can do almost all of their work from within Emacs
Beyond just being able to edit plain text files, Emacs includes special features to help you write in many different human languages and programming/markup languages...
Not my cup of tea but a brilliant tool non the less. I went the vi route :). Pros: Depth of functionality, coverage, flexibility. Cons: My little finger gets strained constantly holding CTRL.
It tries to do it all, I prefer more specialist tools for for specific tasks, yup vim . Pros: Brilliant set of tools. Cons: Overly heavy for me.