That's what I meant: the Sonos is meant to be used in a multi-room environment, where you can stream different sources to different rooms. You can also play music from your NAS, stream internet radio and use music services withouth your smarthpone or tablet or PC having to be connected all the time.
The other units are just speakers with Airplay. If you are only looking for music in 1 room and are not planning on expanding later, you're probably better of with an Air 200 or similar since they will provide better sound quality for the same price.
That being said, a single unit will never give a real stereo image. With Sonos you can fix this by pairing 2 Play5's as a stereo pair, with the Airplay speakers this is not possible.
"The old fashioned way" will be better in terms of sound quality, but you can't move it from room to room like you say.