When I found Clojure, I felt it was more readable, had access to many interesting libraries, and had performance that was as good or better than Python in many cases. The ease of concurrency/parallelism is also very slick, and I suspect it will come in handy to me down the road in our multi-core future. The rise of Incanter, an R-like statistical package, pretty much sealed the deal.
The biggest headache has been the need to work with Java's build systems (not because they suck but because I have no interest in learning them beyond what's required for Clojure).
I have been using Clojure for my work for several months and for me some of the big wins are:
1. easy to use existing Java libraries
2. lots of nice language features like destructuring, etc.
3. nice integration with Java and/or Scala projects with IntelliJ
4. fairly good runtime performance
And, a few hassles:
1. error stack traces have relatively little value.
2. The Clojure team is doing great work, but I still feel that the platform is not quite there yet compared with Java, Common Lisp, Haskell, etc.
I am in a patient mood in regards to Clojure: I use it for some things now, and expect my percentage use of Clojure over other languages will steadily increase over the next few years.
"Poor / incomprehensible error messages and stack traces are far and away the most common complaint."
I mostly use Java for Hadoop machine learning work, but I may transition to Clojure in the next few weeks (my CTO has suggested this).
Earlier this year, I added Clojure examples to my last book on the Semantic Web.
http://muckandbrass.com/web/display/~cemerick/2010/06/07/Res...
So mostly java, ruby and python people, and relatively few lispers.
http://www.sharingatwork.com/2010/07/likelihood-a-user-of-on...
http://muckandbrass.com/web/display/~cemerick/2010/06/07/Res...
Quite a few Ruby and Python people trying Clojure out (much more than Lispers).