Depends what you're making. http://www.joelonsoftware.com/articles/HighNotes.html can apply - what I'm working on right now with Spark I dread to think how you'd do reliably in any other language.

> $500 a day to pay for a scala engineer. Not a word about the bottom line.

Maybe - I don't make that much and I have 5 years' Scala experience. (I have a relaxed environment and great culture though, so I'm not complaining). What I really don't get is Java companies where developers are chomping at the bit to use Scala and management says no - your devs are volunteering to become devs that companies would pay 2x for, the least you can do is let them.