does it have spellcheck? text-to-speech so you can have it read back to you? A browser window would have those things (on a mac, and I assume there's equivalents in windows)
Funny, Firefox on Mac sure doesn't integrate with the native text to speech, or offer it's own without plugins as far as I can tell. Gee it's almost like all browsers aren't exactly the same
And yes, of course Vim has spellcheck.