It's important to look beyond just components when comparing these component libraries. It's safe to assume that most have very similar components at this point.
RichFaces 4 is more than just a component library, it's a rich framework for JSF providing:
Over 100 rich and Ajax componentsSkinsClient-side validation (extension to Bean Validation)CDK (Component Development Kit)
RichFaces 4 is JSF 2 based with a CR (Candidate Release) version out very soon. From there, we are just a few weeks from the final version. I know version 4 took a little longer than everyone expected but this version is more than just a typical update. It’s a significant upgrade that includes the following:
All JavaScript is now based on jQueryAll component were reviewed for consistency, usability, and redesign following semantic HTML principlesBoth server-side and client-side performance optimizationStrict code clean-up and reviewNew and easier to use CDK (Component Development Kit)
I think it's well worth the extra wait.
Installing RichFaces 4 has been simplified as well. Just drop the Jars into your project, nothing to register in web.xml file anymore.
If you look at Ajax features in JSF 2, then you can see it was greatly inspired by the RicihFaces a4j:support tag. Plus, many components have Ajax built in as well.
The RichFaces community is very active and always willing to help. And don’t forget that RichFaces is backed by JBoss and Exadel.
RichFaces might not have the shiniest components. It wasn’t the first with JSF 2 support. (This argument will be mute in about 1 months). But, probably most important, keep in mind that RichFaces is used in thousands of projects and has been proven in small, large, and enterprise projects throughout the years.