[Apologies to SÃ©an for going off topic. :flower:]
We used to have the original Dyson cylinder vac and weren't impressed.
Various bits of plastic broke easily and a lot of dust went straight through the cyclone. When someone sucked up a modest amount of plaster dust the whole thing died. The dust had gone straight through the cyclone, clogged up the filter (yes, they do have a filter to clog up) and moments later the motor overheated (it ran pretty hot even at the best of times). Fortunately the thermal cutout had done its job and reset when everything had cooled. Needed a new filter though.
Fast forward a decade and a similar thing happened to our new Numatic Micro-Filter (somebody hadn't learned their lesson). It carried on working, but people complained of some loss of suction. Eventually it was brought to me to look at and I feared the worst - this model has additional permanent tertiary filters which are expensive to replace (I think it is intended for use in hospitals & operating theaters!). But the inside was spotless. The disposable bag had contained all the plaster dust.
Another reason I like the Numatics are the bags. They didn't hike the price when they changed from paper to cloth bags. Their 'Hepa-Flo' bags cost a fraction of what other manufactures charge - I have paid as little as Â£0.45 in packs of 10.
Before we got the Numatic we had a Miele (just about every plastic part which could break did so within 2 years - so much for paying for quality). Last time I looked they had hiked the price to Â£3 per bag!
[Tip - Numatic 'Henry' bags can fit a Miele with minimal modification, and work a treat. ]