I have been going most of my web app development in Clojure. For many years, I did most in Sinatra or Rails. I would argue based on my own experience that Clojure + Noir are every bit as quick and Agile as Ruby + Sinatra because of auto-reloading of Clojure, CSS, HTML, etc. in dev mode. (Yeah, BTW, Noir is deprecated but I still use it on 4 projects.)