Well, we have been skiing with Mark Warner for the last 12 years, so that speaks for itself.
The selling point for us, originally, was the ski hosting, as my partner and I ski at different levels. It was great for both of us to be able to ski with a group of the same abilities. Sadly, the truculent ESF have put an end to that for now.
However, Mark Warner still offer great holiday accommodation in the newly refurbished Aiguille Percee, which is just about as good as it can get for location- 200m from the lifts with good food which we tend to over eat, and friendly, helpful staff.
They have just about got most things sorted now with a new ski/boot room and automatic boot dryers, so the boots were always warm and dry in the morning - they really work.
Only minor (easily fixable) problems were slight lack of wardrobe shelving and wall hangers (only 3). Our room had an idiotically placed shelf right above the bed-head which prevented sitting up in bed to read an on which I banged my head at least once a day, or more often, in the middle of the night. Wear your helmet in bed if you get room 301