Shale and facelets vs. Shale and Clay

[Randahl Fink Isaksen]

Has anyone got any impressions of the two different combinations shale + 
facelets and shale + clay? In particular I was wondering:

1. Is shale *completely* separated from clay so that using facelets 
instead of clay does not break anything?
2. Has clay got any advantages over facelets when used with shale 
because clay was built for shale whereas facelets is meant for any JSF 
platform?

Randahl