Dense and very complete into learning a Lisp. The one HUGE benefit is I see Racket moving into the most modern programming Lisp. Racket really looks like it has a future.

1) Concurrency and Parallelism (Without pull all your hair out) - http://docs.racket-lang.org/reference/concurrency.html

2) Great Documentation http://docs.racket-lang.org/reference/index.html

3) It will make you a better programmer in other languages

Racket's biggest problem - It's fun to use so everyone has their own solutions for many common problems.