I've really enjoyed using light table.

I spent a few solid days using it while implementing a spreadsheet into a webapp (I wrote the algorithm in clojure and then migrated to clojurescript).

Immediate feedback and live tests felt natural.

Given my clojure is rusty it was helpful to be able to see how functions work with little test cases.

The lein plugin is a nice addition. I'm looking forward to seeing it trigger a refresh when project source files change.