Scheme is still a bit stuck in the multiple-implementations-none-of-which-fully-implement-exactly-what-you-want type stage.
EmacsLisp is like Ruby, but better. One implementation (basically all the others are gone) and lots of people hacking on it and making it better.
The ways it differs from Ruby are that it's a proper Lisp (macros and homoiconicity) and that all the development and debugging tools are built in. Edebug is a fantastic tool for example.