I'm learning Rails and I feel the same way as David Geary about learning new tools:
I am a Rails convert, because first and foremost, I am a maven. I love to learn, and even more, I love to teach. And I absolutely love to learn new technologies.
I believe that both JSF and Rails have their place. JSF is better suited to conservative organizations with complex needs and Rails is better suited to folks who are willing to take some risk and whose needs are not as complex.For me, Rails is currently shifting to mainstream, it will (or is already) a bigger success than Zope and may replace Php for rapid web development.
But I will not junk Java, I do love this language too.
I'll just use the one who suits for the context where I'm using it.