Sonos is very nice, but the £699 price tag vs £280 for the duet is just way too much, plus the Sonos control is massive, and they have no plans to update the range for the next 10 years AFAIK
I think the Sonos was actually nearer to £900 before the Duet arrived.
The lack of net radio is poor as well, never realised the Sonos couldn't do that
