[Mikera]

Note: you don't need to commit to Emacs to get the productivity benefits of Clojure.

Eclipse with the Counterclockwise plugin (and I believe IntelliJ with Cursive too) also give you comprehensive REPL, s-expr manipulation and paredit features.

[ane]

The benefit of CIDER (the Clojure Emacs development environment) is that it now has a s-expr based debugger, whereas Cursive's debugger is still call stack based. So you can traverse the AST like in any other Lisp debugger and evaluate and manipulate s-exprs as you go.

[huahaiy]

vim with fireplace.vim and paredit.vim plugins are pretty nice as well.