I have tested several speakers but here is strongest for its size by the sound.
To be comfortable and also by several Sonos to pair devices, you need a "Bridge" - this is also currently free until 31.12.2013 with it. The device is basically the private router only for boxing and is therefore extremely stable because not everything is going through the normal wireless router (the SONOS Bridge but must, of course with your router are connected by cable). Everything was great - but the Bridge there is only white in color. It would be really useful to choose to give the customer the option - as in the boxes also.
Otherwise, a great system - buy recommendation.