Haven't had them in powder yet (all gone here in VT) but I have ridden them in 2" of slush on top of harder snow, and in several inches of corn/mashed potatoes and on some pretty icy hard pack.
So far I'm blown away at how versatile they have been - really easy to turn, stable at speed and super fun to turn. No appreciable chatter on hard pack and good at holding edges. So far my only worry has been how well the dynafit will release/retain as I ride them harder.
They also have a really nice feeling 'swing' weight - enough weight to feel solid but light enough to make quick jump turns very easy.