Does anyone have one of these?  Are they worth the cost over that of a floor standing fan?  Are they silent running?

Yes we have.  As a heater they are brilliant and cheap to run, the cooling is good but not very good. Better than a fan but for the price you could probably get a new aircon unit and the new ones are excellent

Don't have Dyson, but we have Trotec floor fans which we bought from Amazon es, they are extremely quiet, remote controlled, easy to assemble and have 8 speeds.  59.99€.

Thanks for responding!!!
I have 17 year old air con which is very expensive to run and I haven't used it for about 15 years as it had a dreadful affect on my sinuses. The floor fans I have are great during the day but far, far too noisy at night, hence my question.

Forgot to say they are A rated and set on 4/5 you don't know they are on.

Many thanks, Roscoe!