Which? annoys me in various ways, but not taking the cost into account in their ratings is I think actually one of their better moves. In your example, you can

Which? annoys me in various ways, but not taking the cost into account in their ratings is I think actually one of their better moves. In your example, you can see very plainly that the Electrolux is a much better buy. If they'd included cost in the rating, you'd probably be left wondering whether the Dyson was worth the extra.