I recently started on developing in PHP with the Yii Framework. I recently came across the Grails Framework and I'm pretty impressed by the sites they make, bigger companies seem to use Grails for their web development. When looking at yii, not many big companies are using it. I'm just starting out with the Yii framework and I don't want to turn back halfway when in the middle of learning Yii, so I hope someone can give me some comparison about the 2 in terms of power. Does Grails make things much easier and benefit me in the long run? I only have C++ background for now.

It boils down to this. I want a powerful framework which will serve me for a very long time and by looking at the number of big companies using Grails, I feel discouraged to take the Yii path.

Thank you!

Some sites by Grails:
http://video.sky.com/
http://espn.go.com/
http://www.atlassian.com/
http://www.linkedin.com/