Petek et al - That's the problem with these companies. The info you get isn't quite in depth enough - which is why review sites exist giving individual experiences from actual owners - I don't believe CR or even the UK equivalent WHICH UK is the "god above all" for data tests on vacuum cleaners let alone household appliances or indeed anything else they publish.
Because of the way vacuum cleaners are required to be used in so many ways such as cleaning on different types of surfaces, to hard floors, to the use of the smaller cleaning tools, to maintenance, changing the filter/washing/buying/changing a bag, weight of the actual individual floor head, tubes, length of hose etc - these requirements are seldom reflected in tests and are consistent with every brand.
CR, WHICH, GHI - they're good at their marketing and they're good for promoting the brands - but when it comes to actual testing, they can only go so far. Sadly for collectors though and for those who pride in machines, it's never quite enough to just read baseline reports and I'm sorry but brands DO bribe consumers AND testing companies.
One company I can think of who are bribing UK consumers at this moment are Vax. Since they merged with TTI and Dirt Devil, they consistently send out free machines and appliances to consumers in the agreement that they will write up a good review about the product to promote the machine, thus cutting the cost of actual advertisement. I became a member of their product trials but they know me well from the product reviews I've written over the years - I write what I feel is honest - and quelle surprise, Vax have never sent out a free machine to me yet! Bad publicity isn't what brands what, whether it's the truth or not!