Brief update--
After installing a Sonos system as my non-main system, I have to say I am shocked by what out and out garbage this product is. I am furious that I invested in it.
It has repeated, regular dropouts and software hangs -- despite that I have 200MBps WiFi throughout the apartment that was professionally installed (along with the Sonos, which doesn't need a professional, but it came all together), with a switcher, and my place is not large by the standards of a normal detached U.S. house.
The feature set sucks. Cannot import my iTunes playlists, rendering that library useless (since I can get the files on Spotify anyway). Has spottily imported my FLACs. Spotifiy, the predominant music service, has no 'album" function or "radio" function, so you just have to sort of think about albums you might like and play them. Deezer, the new French service, has FLAC streaming and has the "album" function, but its hanging issues are worse and plus fewer people use it. I can't just leave it on during the day to provide some background noise, because it invariably shuts off, even on repeat or a Pandora station.
As to the sound quality, it's OK for a bedroom or kitchen speakers, or outdoors, but by "OK" I mean my powered office computer speakers would smoke this thing. The dual Play:1 speakers in my bedroom can't really fill that room with sound... again, we're talking about an apartment bedroom. The single Play:3 in the kitchen is fair, about as good as the Bose speaker of the same size. The connects I have hooked up to my reference system and my office system (which is also pretty nice) work sporadically and their quality is nothing to write home about.
All of this makes me wish I had kept my several Airport Express WiFi units, as my homebrew Airport-based multi-room system was vastly more reliable and cheaper to implement than this crap system. Sonos' "ease" is only relevant if you literally have no idea how to set up any kind of legitimate audio system.
I have contacted Sonos, and heard nothing back except "Send a diagnostic". Which I did, and now have heard nothing.
They, and the pro audio installers who set the system up, are about to receive back a box of junk and a request for a full refund. I am stunned that this product is this popular.