I would add a few more:

Pick Scala if:

    -You find value in strong static assurances.
    -You find value in generics.
    -You want to learn functional programming, not 'functional' programming (and you should).
    -You value succinctness.

Pick Go if:

    -Compile times matter (of course it does).
    -You find value in easier deployments (at the cost of potentially more deployments).
    -You don't want to learn D ;)