In ideal conditions (connection to internet) the app works ok at best.  The alarm function to play a radio station fails most days.  It will play from 2 minutes to 1 hour when set to play for 3 hours on alarm. Volume management works well about 50% of the time.  This week we had an internet outage for about 6 hours.  Sonos would do nothing.  I should be able to play local files, but I could not even log in.

I know you are working on the issue, at the end of the day if all commands have to go through the cloud the system is only as good as the internet service of the customer. Much less the local network environment which is why you have your own back channel that makes the system more reliable.  Many customers have high latency service.  My Ubiquity system monitors my threshold, and it rarely goes over 32ms. 

I owned a fairly large healthcare company that connected to medical devices.  Even under contracted services we could not rely on quality to be high enough 7/24/365 and had to have local cache.  This will not get resolved until you go back to some forum of that model. Please do!!! I like Sonos very much.  As I look at future purchase though I am comparing alternative as the current state even as it has improved is not functional.