We’ve got Sonos throughout the house, 5 or 6 boxes – built up over 3 or 4 years and whilst a little sceptical to begin with, I love it.
Good points – so easy to set up, as close to plug and play as I’ve found. Sounds quality ranges from decent using the ZP120s through to absolutely excellent with the ZP90 through a DAC and Amp. We did a back to back test with my CD player through the same amp and speakers and the difference was (disappointingly, given how much the CD player cost) minimal. Interface with Napster, Spotify, Last FM etc is excellent and works seamlessly with iTunes. iPhone / iPad apps are free and as good as the controllers (much better than the old style controllers in fact). Now works with OSX Lion too.
Bad Points – it’s not cheap. Having said it’s plug and play, when I merged two iTunes libraries, I had some difficulty getting to recognise the whole lot, although that’s more my fault than the system.