laax itself isn't esp big. it might be part of a big area. the biggest is 3 valleys in france (600km of pistes) and portes de soleil in france/switzerland.
most vert would probs be cham, zermatt or possibly tignes...
Laax is more a freeride and freestyle place. There aren't very many slopes, 46 km black, 71 km red, 63 km blue and 40 km of ungroomed slopes (but this is europe so if you wanna go OFF-piste, that's also possible) and it has got a lift only for freeriding. Don't to mention 2 huge funparks and the biggest halfpipe of europe .......