I have the old 03' Teneighties, and man, they chatter. But they do so like any park ski of that stiffness. Foam cores can be nice, no doubt, as Nomensteven says, otherwise Saloman would be out of business. However, there is one nagging thing about my skis that I really think is because of the foam in the core: The flex pattern. For some reason, its really really hard to butter on my skis well, just because the rebound of the skis is so immediate. With wood, the flex takes a little more time to bend back into its natural position, but I think that the foam cores snap back quicker. I kind of like that leeway in the rebound, and all the other wood core skis's I've ridden have that.
Foam isnt a bad thing, true. However, just for me, I would prefer a wood core ski, just cause they're better in my opinion to butter (and also because K2 uses wood cores in the Maden's). Who knows, maybe foam exceeds where wood doesnt in some way, maybe like overall stability or weight, but lets face it, the differences are really minute. Only people with too much time on their hands can really argue that one is really better than the other hands down.
"What if the hokey pokey really is whats its all about?"