AlmaataKZ:
Here is a question -
With all these "airplay" capable gear coming out, is it worth considering an apple 'airplay' based sytem instead of SONOS-based? How would it compare in functionality, stability and cost?
is the question worth a separate thread?
It may well be worth another thread, but my experience of a system based around apple airport expresses was what led me to go for Sonos! Unfortunately any system that piggy-backs on your existing wifi network is going to be inherently less stable than Sonos, which uses it's own wireless network and creates a mesh where every component acts as receiver and sender. They also offer a very thorough and responsive support service - try contacting Apple if you have an issue!
With using your existing wifi network it's not only an issue of sharing bandwidth with other network traffic, but interference caused by neighbouring networks or other devices emitting signals on the same frequencies, which would normally go unnoticed or maybe manifest as a momentary slowing of your connection, but will cause drop-outs if you're trying to stream music files.
With the Apple-based system I had incessant wireless dropouts when playing music, I tried everything that the collected knowledge of this and other forums had to suggest and could not solve these issues. Since moving over to Sonos I can count the number of times that it has dropped out on one finger, and actually i suspect that was my Apple Time Capsule (where my files are stored) doing something strange.
In terms of the interface, functionality and flexibility the Sonos is second to none. The Apple system based around iTunes/Remote is cheap, simple and provides a great interface, but it really isn't a competitor in my view (e.g. you can't play different things in different zones).
Hope that helps.