The Lisp guys make the productivity point:

Rails is not a Silver Bullet. However, widely reported results place productivity increases over modern Java methodologies (e.g., J2EE, Struts, etc.) in the 6-fold to 10-fold range (with many of these claims coming from long-time Java luminaries). Preliminary tests by our Technical Lead put the code reduction for a normal module in our Java stack converted to Rails at roughly 20:1.

This is what you would see with Smalltalk (or Lisp, etc) as well. If you want a leg up on the competition, you won't find it with Sun or Microsoft.