I visited Champagny a few years ago but doubt the resort would have changed much in that time. It's a typical small French village set up on a steep hillside, reached after a hair-raising drive with long drops!
Its main advantage is that it is a cheapish way to ski La Plagne, which it is linked to. The village is split in 2 halves. It's better to be at the top next to the main (only) lift! Stay in the Club Alpina which is more or less next door to the lift, the foods good too.
If you stay in the lower half of the village you have to get an escalator up to the top half as the hill is too steep!
The skiing faces south and it gets a lot of sun, not good later on in the season. The local slopes are fairly bare and not too interesting, but the views over to Courchevel are fantastic. Which is another reason to stay here. We skied Courchevel on the same lift ticket as they have a 2 day arrangement to ski at different resorts in the valley, it's about 20 mins away by car.
The links into La Plagne are good and well signposted so no problems. The local nursery area is small and steepish for 1st timers.
Overall a very pleasant place to someone who wants big area skiing on their doorstep with the option of skiing Courchevel.