I work at Factual, which I'd estimate has about 20 Clojure engineers. We've found folks generally enjoy working with the language--both newly hired programmers

I work at Factual, which I'd estimate has about 20 Clojure engineers. We've found folks generally enjoy working with the language--both newly hired programmers who already use Clojure, and internal converts. Code structure for maintainability is always a concern, but because Clojure doesn't impose as much rigid OO hierarchy as other languages, refactoring is a little simpler, I think. It decimates your hiring pool--but the programmers who are fluent in Clojure or other Lisps tend to be skilled. I also think Clojure is more concise and more productive than, say, Java--which reduces the volume of code, and lets you do more with fewer people. Keeping the team small reduces the number of meetings and managers, and keeping the codebase small makes it easier to understand and maintain. YMMV, naturally--but I wouldn't consider these concerns as insurmountable obstacles to using the language in production.