I voted for Netbeans, because it is a really great IDE, it's free and I love it for its maven support. Nevertheless, I think that those PrimeFaces specific plugins are a little overrated. They are nice for scaffolding and rapid prototyping, but that's it.
IMHO, IntelliJ has the best overall JSF support. Oleg already gave a few examples. If I could have voted for both, there would be one more IntelliJ vote
And also: In my opinion, it doesn't matter if IntelliJ is a commercial IDE or not. As we all know, without sponsoring both IDEs (NetBeans and Eclipse) could never be offered for free. So I think it is fair to compare them.
By the way: The Android Development Studio (Based on IntelliJ) became freely available, since Google sponsors it: http://developer.android.com/sdk/installing/studio.html