And how many people running Scala are actually using those other JVMs? How many of them even compare to the Sun/Oracle JVM? I mean, honestly? And given Oracle's new penchant for suing people and their spat with Google/Apache, do you really want to keep your eggs in that basket?

People keep trying to sell new languages to Java developers using the JVM. The problem isn't the language, though, it's the JVM itself and the licensing problems, too.