Spring roo is new framework and I found it very interesting. I have been working on web application for last 3-4 years and Always found JSPs are hard to maintain across teams if
I was at the SpringOne conference in Amsterdam earlier this year when they announced Roo. My impression (and that of my colleague who was there) was that Roo was good if you were generating a web-based CRUD application every few weeks - they pitched it as the pure Java version of Grails (which is RoR for Java).
Didn't look interesting for anyone else - but that's just an opinion.