I am not a software developer.  I am, however, interested in software engineering as a science.  I recently ran into an IBM article that makes the following claim:

The argument against wild productivity claims usually goes something
like this: If I’ve got a decent hammer, I’d be hard-pressed to find
another hammer to make me twice as productive, let alone 5 to 10 times
more productive, because hammers have evolved over thousands of years.
But people who compare Ruby on Rails with a mix of general-purpose Java
frameworks are missing the point. You can be 10 times more productive for some problems
by radically changing the nature of the tool. Professional framers now
use nail guns that can drive in dozens of nails in the time it takes to
hammer in one nail. Like nail guns, Rails is specialized. It’s a
framework written with a laser focus on a single niche: new database-backed Web applications.

For our new web-based project, my partner Cagan picked RoR as the development framework.  We are also very happy about our choice, although, I don’t know that he would claim a 10X producitivity gain.