My opinion is that clojure has a confluence of just right abstractions and language choices that allows you to be very very succint while still very readable which in turn makes the language very expressive. I can name a few features: immutability, multimethods, protocols, transducers, lazy sequences, macros, and a very small and sturdy core. All of these features exist in some other language, but the combination of them together is what makes clojure great IMHO.

Besides, experienced clojure devs just see things differently and end up writing lots of nice libs that capture the essence of the feature the lib is providing. Think datomic (immutable database), reagent (interface to react), honeysql (data-as-sql), "dependency injection" (mount/component & others), pull/query-based UIs (om.next and its spiritual successor, fulcro) and so on.