I'd have a small preference for Eclipse, mainly because some specs are already there (like EclipseLink).
Apache already has their own implementation of much of Java EE (via the Geronimo project, TomEE and Tomcat, among others).
In my opinion it would be slightly confusing to have say 2 JSF implementations at Apache (Myfaces and Mojarra). Not really terrible, but my gut feeling says Eclipse would be a better home.