The system's stability is not acceptable and my user knowledge is too low. It is too difficult and time consuming to build my own technical competence which also indicate that the Sonos web site is not tutorial enough (it's really focused additional sales). And the system is simply not user-friendly enough. After years of frustration, the Sonos support recently informed me that there is an upper limitation of how many units can simultaneously! So I've spent money on buying units I don't need!