Oz is quite well connected by road to Grenoble and the rest of France. It's a small, family-friendly resort linked to a sports area, and has remained relatively untouched by over-development. There are a few shops, a tourist office, and the ESF ski school, but it's very peaceful: a few activities are offered besides skiing.
Since it's located at an altitude of 1350m, snow conditions can sometimes be an issue, but thanks to excellent access to the Alpe d'Huez ski area, good snow cover is guaranteed across the entire resort at the beginning and end of the season.
I recommend it for experienced skiers looking for tranquility!