The Fantom used a better motor and filtered better in cyclones due to it. I know Fantom used and licensed Dyson technology but I don't think any vac using it better implemented it than the Thunder. Bear in mind original Fantom models didn't use a filter, neither did the Rainbows. If you want a modern machine I know a current Dyson can't outclean a current Rainbow. It is more on brushroller and powerhead design. You can argue about costs but if the Rainbow costs three times as much it is money well spent, it probably will last three times as long. I'd hit a Fantom Thunder with a baseball bat and it probably would survive, a Dyson I'm nowhere near as comfortable about.
Now I've got nothing that much against Dyson, my main gripes are their advertising claims, cost and build quality. Industry standard tests are one thing, real world is another. It won't outclean a Kirby, Rainbow or many higher end vacs. They cost a lot for what you get. They aren't built terribly well. I just know if I was paying retail price, which I never do (a personal philosophy of mine), I wouldn't own a Dyson.
