Scala is getting really interesting lately though with projects like Spark and SparkSQL. Spark takes a Scala AST tree and computes a plan on it in order to distribute it to a cluster of possibly thousands of nodes and then uses transformations on that plan, similar to how an SQL query optimizer works, to make the plan more efficient. The cluster compute benchmarks on it are crazy good.

The only problem I have with Scala is that it has so many features that it tends to have a steeper learning curve than most languages. However, this is mitigated somewhat in that it lets one switch between object and functional depending on what's more convenient or performant, thus making it easier for programmers who are not highly skilled in functional programming to pick up.