I bought this system, and despite a good level of investigation, discovered some aspects that made it unsuitable for my use. So it is worth carefully matching its specifications against your requirements.
My requirement was to be able to play music from my iTunes libraries, play internet radio, and control without wires from (Windows) laptop or iPhone. I have about 30Gb of music in my master library, on the laptop, and a 20Gb subset on my iPhone.
During set-up, and subsequently on adding music, the Sonus system builds its own index from one or more PC or Mac held iTunes libraries. (So every time you add tracks to your iTune library, you will also need to do the Sonus index building operations to get that in sync. Not a real deal breaker for me, but a minor nuisance) It will NOT be build an an index from a library held on an iPad or iPhone. The index enables the display options similar to iTunes - e.g. search by track, artist, album, and can create playlists (rather better than the iTunes playlist facilities). So you can direct what you want to play from an iPhone or iPad (via the Sonus app), but the actual music that is played will be from the PC or Mac. So if your laptop goes into hibernation or is switched off, the music stops. This can be pretty inconvenient.
The issue that was more of an issue was that when I sat down and used the laptop to play music whilst I was doing normal browsing of the internet, I noticed that during any data heavy downloads the music became gargled or even stopped with error messages displayed. My wi-fi network (BT hub2) generally works pretty well, but not good enough for running the Sonus system and normal activities. Discussing this with the Sonus support people, we discussed using a NAS device connected to my router, and consolidate and move iTunes libraries onto this. As well as reducing the level of wi-fi traffic, and being an always-on device, not require a PC to be fired up each time you want to play music.
So I bought a NAS device and spent a complete day getting the thing installed, encountering various bugs in the set-up, and requiring 2 calls to their support line. Then nether I nor the support people could get the iTunes library files copied to the NAS to work. I decided to call a day to this whole exercise and returned both the Sonus system and the NAS.
So instead I plugged a bluetooth receiver into the aux socket of an existing Bose Wave Radio, and a USB bluetooth dongle in my laptop. I can now play music as held in either my iPhone or laptop, and play internet radio from the various apps available.
What I cannot do is to play different tracks or playlists in different rooms, and control the whole set-up centrally - as the Sonus system allows.
The Play:3 speaker system itself is a neat and elegant unit, and has adequate volume for a medium sized room. The quality is equal to my Bose systems - it doesn't have thumping bass, but was perfectly acceptable to me.
The Sonus support people are available via a toll free number. The first guy was extremely helpful the second guy was pretty average but did configure the Sonus system for the NAS ip address.
So I was disappointed that this system didn't work out for me. Had I got the NAS system up and running quickly, I would have stayed with it. But had I realised the Sonus limitations before purchase, I wouldn't have bought it, as these outweighed the unique Sonus advantages. Instead I would have looked at something like the Bowers and Wilkins a5 system that has Airplay and (vitally for me) bluetooth as well.
Update: (5th Dec 2012)I just received an marketing e-mail from Sonos that announced that software & app updates are now available that enable you to play music direct from your iphone or ipad, i.e. (I assume) that you no longer need to have a pc or mac switched on and running before you can use (say) an iPhone to play music. I guess you need to check out the Sonos web site to confirm this does what you want. But it does seem to satisfy my basic requirement - to be able to play music from my iPhone without needing to switch on my laptop, or play from my bigger iTunes library on my laptop, when needed. There is still a risk that if your home wi-fi is not optimal, you might get music cut-offs when, separately, using the network for other intensive operations. (As I experienced and a great many other happy users had not) Had this update been announced before sending my unit back, I think I would have kept it.