I have ample Java experience and had been using JavaScript and Node for three years now. I have spend quite a lot of time programming in Clojure with just toy examples and am building a simple game to get a handle on it from a more practical standpoint.

That said I too still can't figure out how to use leiningen and it seems clunky and slow. It's also easy to find examples that don't work. I'm not sure if getting it to work with as little hassle as npm would help it's growth, but seems like it couldn't hurt.