Yeah, I agree with this, other than not having used Scala. Static typing communicates intent to the user of your functions, they help you think about the problem before going all-in.

Rich presented some new ideas for where he wants to take Spec, but I didn't think anything very new made it into 1.10 regarding spec.

Personally I use clojure whenever I can. I can quickly build up a project using the fast and loose data types, and when my conception of the project solidifies, I convert over to records and protocols. That's usually enough to get 80% of the way there. The free and loose ad-hoc data structures get me across the finish line, and it's there that Spec comes into play.