For me Clojure is the best Lisp available, JVM platform or not. It's more functional than the other Lisp, use immutable data-structures, have a lot of data types (vector, set, map, list) with literal syntax and unified abstraction on top of them and the macros are easier to write than in the other Lisp thanks to autogensym and name capturing.

Main selling point: it's Lisp and it's the best available.