I would use facelets without any doubt. I started using it a long time ago and haven't regretted it one bit.
The only minus I've encountered with Facelets is the poor support from Tomahawk, not a big issue because there are severl sources for information regarding how to over come this.
Most other component libraries provides Facelets support out of the box.
The IDE support isn't that great(doesn't matter to me though), there are some dreamweaver addons which I haven't tried. 
There also seems to be some development efforts going on within Eclipse WTP .
And then you have Exadel Studio which will (shortly I think) become Redhat Developer studio, not sure just what their facelets support looks like though.
In JSF 2.0 will include some sort of templating support and facelets is being mentioned as something which could be used as a base.. 
Hope this helped a little.
Facelets is a pretty good choise at present.
Red Hat Developer Studio (previously Exadel Studio Pro) has good support of facelets as Visual Editing, content assist, jsfc usage and etc..
As for me works fine with tomahawk using latest versions of both libraries.