I sent a relative to the ski school over President's Weekend last year. The school seems to manage to accommodate everyone, but the lessons are compromised by groups which are too large trying to work in an area which is too small. My cousin (an adult) left the group and it is doubtful that her absence was noted.
The school has a good reputation but the beginners areas are small. I am sure that it would have been a better experience at a less "prime" time.