I have no doubt the Dysons made a decade ago were excellent vacuums. In my experience the ones made the past few years are very much not worthy of the good name.
Although I've had good luck with HP Printers mysef (still own several 4250's higher speed and do plenty of output with high quality) sounds like similar comments I've read about recent HP products.
I've found that this kind is very common; a company will build a good reputation on high-quality products and then slowly lower the quality to make more profit.
It's almost to the point where there should be trademark laws that start to enforce a type of product to protect consumers. Like when Pyrex changed the composition and started breaking. I know it's not feasible to so cleanly draw such lines - for instance, I'd prefer if Lenovo wasn't allowed to use ThinkPad on their current line of items.