Here's Dyson's description with my notes

Patented Root12Cyclone technology - little whirly vortices that concentrate the suction
Low reach floor tool - you can get it under quite low bookshelves, for example
No filters to buy - one comes with it
BAF Seal of Approval
High velocity airflow tools
Car cleaning - two of the heads are particularly useful here
Suction release trigger - if it gobbles up something unwontedly, this makes it easy to release it
Ergonomic wand handle - suppopsedly designed to fit your body!
Adjustable wand -it telescopes by about half
Removable tool holster - see note below
Sits on the stairs - just about, but not if you have little steps
Easy to store - up to a point, Lord Copper
Clear bin - you can see what's inside it in order to know when to empty it
Protective rubber wheels
Robust construction - it seems to hold together well: we've had it for about four years
Manufacturer's 5 year guarantee


OK, they cost a lot, even if you shop around. Somewhere around £150 can be got at the moment. Dyson themselves don't list it any more on their website. But hats off to James Dyson for being so persistent with his prototypes.

First things first, the suction is good. If your previous vacuum cleaner was a normal type, you may notice a disconcertingly large amount of dust and dirt the first time you pack up with a Dyson. This one has twelve little turbo channels that supposedly help it do a better job. This one threatens to lift your carpets! Depite the strong suction, you don't need to be Hercules to use it - and a bit of resistance helps lift the dirt out of the carpets.

The Dyson is fitted with a Hepa anti-allergy filter. These should be cleaned out every six months - a straightforward job, best done just after you have used the machine, unless you have a second filter to alternate while the other one dries.

Cleaning the Dyson itself is good in most respects. It's great that it's bagless, but that's one reason why you might buy it. Being able to wash out the main dust container is very good. (Don't forget to dry it out before re-use, of course!)But it is hard to persuade all of the dust out of the Dyson's innards, and so although the hygiene is good, there's a nagging feeling that some microbes might still survive.

The cable retracts powerfully into the body when you press a button. If you don't watch out, the plug can bang into the side, so you learn a technique of just stopping short.

It comes with three attachments for the head - crevice, brush and mini head for cleaning car seats. They hang on a bracket around the tube - a bit clumsy this, and they can fall off.

Extra to this is the turbo head, which has fast rotating mini brushes, very effective foor removing animal hairs.

Not especially noisy in operation, although our cats usually vanish

Storage is not a strong point, the tube doesn't collapse very much, and is sometimes a little hard to re-extend.

The motor died after two years, but the Dyson man who visited was so surprised by this, he supplied and fitted a new motor free.

All in all, it does the job well, but it's not perfect.

UPDATE May, 2009

Still going strong, but I sometimes wonder whether the suction is as good as it was. No easy way of telling, and it could be simply that I've got used to it.
The tube has got gradually harder to re-extend. Apart from that, it does what it's supposed to.