Here is a list of participating resorts
Savoie: l’Espace Killy (Val d’Isère and Tignes), Paradiski (Les Arcs, La Plagne, Peisey-Vallandry), Méribel-Les Allues and Les Menuires-Saint-Martin de Belleville (we are not sure how this works with the other Trois Valleys resorts).
Haute-Savoie : le Grand Massif (Flaine, Les Carroz, Morillon, Samoëns, Sixt-Fer-à-Cheval).
Hautes-Alpes : Serre-Chevalier.
The following reductions are offered on the one day ticket prices:
* 15% outside the February winter holiday period
* 10 % during the February holidays
* between 25-30% on Saturdays (change over day for week holiday makers)
This is actually a lot less generous than the CSF pass (which, according to the website) offered a 30% blanket reduction.
The CdA claim you are better off with the Holiski pass after just 8 days skiing. Which is true if you always intend to ski a single day in each resort say once a week during the season. However some skiers might do better to look at the CdA’s XXL if they are staying in the Tarentaise for one or two weeks.
You said “Méribel-Les Allues and Les Menuires-Saint-Martin de Belleville (we are not sure how this works with the other Trois Valleys resorts).”
I asked Holiski that question and got back via email “The Holiski pass enables you to ski in Les Menuires but not in Courchevel. If you want to ski in Courchevel you wont be able to use your Holiski pass and you will have to buy a pass for Courchevel”
So pretty pointless for a daytripper to 3v unless you want to ski just one sector.