I think it's good too with other cheeses like St. Nectaire farmhouse or Mont d'Or, but of course this is not a "true" tartiflette.
Is this a true one? Not really says Julie (born in the region) who tells me that the potatoes should be fried in a pan before going in the dish. Nathalie, from Bellegarde, on the other hand, doesn't cook the potatoes, she just puts them into cold water and stops when they come to the boil. Well, as you see, one recipe but many versions...
All the proportions indicated can be easily changed according to taste.