Personally, I've been doing Drupal for a few years now and found the knowledge and skills to be a lot harder-won than the knowledge and skills that I've picked up with Rails in the last few months. The knowledge and skills that I've picked up working with Drupal (HTTP, Databases, etc) more or less translate into general app development, so that surely has something to do with it.
I said this to my wife this morning - "you know what, building stuff in Rails just feels like it accesses my creative brain more than anything I've done before." Having been exposed to some of what Acquia is doing with their cloud hosting stuff I can say with a fair amount of certainty that almost anything under the sun can be accomplished with Drupal, but that's (the creative bit) probably why I'm on a Rails kick lately. It's just more fun (to me). The overhead does feel lower, too.
Sorry if that didn't lend any insight to your actual question.
I said this to my wife this morning - "you know what, building stuff in Rails just feels like it accesses my creative brain more than anything I've done before." Having been exposed to some of what Acquia is doing with their cloud hosting stuff I can say with a fair amount of certainty that almost anything under the sun can be accomplished with Drupal, but that's (the creative bit) probably why I'm on a Rails kick lately. It's just more fun (to me). The overhead does feel lower, too.
Sorry if that didn't lend any insight to your actual question.