Well, I'm not sure if the grades are supposed to be for the movie, or the DVD, or just sorta both or whatever. VAMPYR is a beautiful package with loads of informative extra material. The quality of everything makes it hard to give it bad grade. The movie itself is pretty cool, but its not likely to plaster you to the edge of your seat. I've actually never gotten around to seeing Nosferatu, so I can't compare the two. But based on what I know I'd say VAMPYR is much more a pure mood piece. It's pretty abstract. The actual vampire is an old woman, oddly enough, and you only see her once or twice. The small pool of characters and their relationships to each other are very ambiguous and shifty feeling, with little if any explanation for their motivations, etc. At one point, two characters even seem to change places, in terms of who they are/what they're doing. Yet it's all very meticulously put together, and gorgeously, conscientiously shot. I could see this movie having been an influence on Lynch.
In terms of my actual level of enjoyment sitting there watching through it, I'd give it maybe a B or B-, but even if one found the film frustrating or disappointing, there's so much extra material to put the movie into context and make it interesting as a piece of film history that the DVD is worth it anyway, provided you're fairly interested in early cinema.