To Les Arcs you primarily go for skiing. The ski area is very snow-safe, because you ski at high altitude. Les Arcs has a 7 kilometre long piste, Aguille Rouge, with the single highest drop among the slopes in Europe, 2050 meters.
I liked the area even if it sometimes was a little bit too crowded in the slopes. A tip is not to go here while the schools in France has their winter holidays. We stayed at Les Arcs 1600 which was the first village that opened (1968) for tourism. The village has everything one could need but feels completely built for tourists.