I think the object oriented features of Scala make the language more usable for real world applications.
But the idea of Clojure - tight integration with Java through
Iterator, implementing Java interfaces, but keeping immutable structures, compared to Scala which creates it's own incompatible versions, should prove much more successful. I like that definitely way better, Scala should adopt that approach. And of course implementing STM in Clojure is genius - lots of people talk about STM and it could be the next big thing for sharing state in distributed applications.
Thanks for listening.
Update: Sequences in Clojure http://blip.tv/file/734409