Clojure is designed for the user level and offers some unique advantages over Haskell's STM [1]: * MVCC snapshot avoiding transactions restarts on read

Clojure is designed for the user level and offers some unique advantages over Haskell's STM [1]: * MVCC snapshot avoiding transactions restarts on read invalidation. * Ensure references on read-writes provides a kind of manual control over resource acquisition order. * Has explicit commute which reduces retries on commutative writes. [1] http://stackoverflow.com/questions/4560605/how-does-clojure-stm-differ-from-haskell-stm http://stackoverflow.com/questions/4560605/how-does-clojure-... EDIT: I didn't read the OP closely enough. Yes grafting fine-grained STM onto a imperative language hasn't born much fruit.