Apart from Volkswagen group I would of thought they were pretty accurate unlike the mpg figures. Also aren't the performance ratings actually pretty accurate with only the atrocious Which consumer group complaining because it doesn't match their hopeless poorly designed tests. I mean isn't it Miele themselves that measure how much is picked up and by the average result of particles picked up create their own rating. Is there a single vacuum cleaner manufacturer complaining about this rating system? Also I think there is no requirement to test when a bag is half full or getting near full when suction is much reduced so it unfairly favours bagged cleaners as cyclonic cleaners can be emptied at any time and don't suffer suction loss as the canister fills.