If I had more time – or didn’t need sleep or food perhaps – I’d be interested in learning Ruby and Ruby on Rails, if only to see what all the fuss is about.
As I’ve begun experimenting more and more with PHP frameworks, one of my big worries would be that the frameworks enable quick development but only as a means of hedging bets: the site’s up and running fast but the problems are reserved for later: if a site succeeds, if it’s traffic increases immensely, then the framework could become the source, instead of the solution, to scalability problems. And how do you fix a problem that’s part of the system’s core? Re-do the core?