dont know when you are planning to go, end of this month is the x box big day out at val, the kicker isn't in the park but they are likely to do the park up a fair bit for that event.
Never skied the chamonix park, but i wouldn't think that it is very good as you go to chamonix to ski the off piste/bc, as it is prob the best in europe. Tignes and Val (espace killy) are quite a long way from italy, but not as far as laax!!!
Go on to the resort websides and see what they say