if budget is reasonably healthy, i'd consider a chalet with esprit.
la rosiere is nice, particularly for beginners and children. we have gone a few times end of jan, early feb and it's been great - good snow, some bright sunny days, few queues at the lifts. (although we have exhausted it now and are going elsewhere with esprit this winter)
a chalet means someone will wait on you - i couldn't have managed without that, my first year! i was so exhausted every day that the family would have starved if it had been down to me to feed us!! and because it's just a big house really, you can leave your dcs in their rooms in bed while you eat in the evening. we have mostly found other people to be very nice - have always booked a chalet with several families in it because i have been worried about the horror of a two family chalet where the families didn't get along, or a three family chalet where the other two have come together and you feel left out!
esprit's childcare is great. and the staff have always been pretty helpful to us in the case of illness, nervous children, lost passports/purses etc, sorting out delays etc.
chalets aren't necessary luxurious, but are generally nice and clean.
you can fly to chambray to reduce your transfer time (lots of vomiting as coach winds up mountain - be warned!), but our experience has been that we are nearly always delayed in and out because of fog...this is a chambray problem i understand!
lots of people put their dcs in lessons/clubs all day, but tbh we want to spend some time with ours when on hols, so ours go to lessons in the mornings, and we book lunch for them (which gives us time to have a grown up lunch somewhere - or just a rest!) and we all ski/sledge/play super mariokart on nintendo ds/build snowmen etc together in the afternoons in addition you get a whole day together at the end of the week...and sometimes we let them skive
our dsc are 8,9,10,11 and this suits us down to the ground...but we are planning a budget self catering version next winter to save money. we tend to have to book ahead in order to get accomodation that will take us all, but you could probably book last minute and get a real bargain!! have a look at their site