From sources... There's not much overlap between the Scala and Clojure folk, so nothing to do with any "growing pains". Scala's seeing much more uptake than Clojure.
Parenthesis are always offputting to me, even though I like a fair amount of clojure concepts. I often feel like functional programming has made a cottage industry around putting obfuscated names around relatively simple ideas (see transducers for example)