I don't diagree with you on some of the Dyson products being gimmicky with a premium price tag, and the air purifier does look suspect to me. However, the Dyson v11 cordless vacuum I just bought is phenomenal.

It has far better suction and cleaning effectiveness than anything I've ever used - which is partly why I bought the v11. Our mains powered central vacuum just wasn't cutting it, and was bothersome to use.