Thank you all so much for these excellent and detailed answers! This is more than I expected but exactly what I was hoping for.

I followed Alex's recommendation and have cross-posted to the Grails mailing list: http://grails.1312388.n4.nabble.com/Greenfield-development-Tapestry-or-Grails-for-Groovy-dev-td4636279.html

Please don't let my "thank you" now dissuade you from adding your own response. I would like to hear everything I can on the subject.

Thanks Again! Sean