Lately RichFaces gets more stability and it's very good (but still not perfect). Also component list is rich and probably complete for all basic usage.
So what RF can offer in future? More components?
GWT is different and offer more "live" interface. RF has two ways: do similair things using Ajax, or adopt GWT as component.
I think a second way should be choosed. It's possible - let's look at http://weblogs.manas.com.ar/mverzilli/?p=4