We have now had the new Sonos App for 3 months, here is what I have discovered so far.

• The old App is not coming back. I am not sure if this is down to Sonos being stubborn or inadequate planning for this as an option. Either way it is not coming back.
• There will not be a class action law suit. Simple truth is that, no matter what it feels like, our speakers still have the capabilities we paid for its just that the App won't let us access them effectively. The possible exception here is the users whose speakers appear to have been "bricked" by the App.
• The new App has some fundamental design issues and is generally slow to respond for a number of users. My personal experience is that changes, like volume, vary from instantaneous to 20/30 seconds to be applied. 
• I still don't think the new UI is "intuitive" but I have got used to its idiosyncrasies. As others would put it I have developed the requisite "muscle memory".
• The new App clearly works for some people but that does not in anyway diminish the issues that many are seeing. In my opinion this just reflects the poor design of the new App and the lack of adequate testing.
• Blaming the user's network is a flawed response first because the old App worked on that network and second because this is a consumer product and it should be designed to work on a consumer network. If Sonos expect all their users to be network specialists they will be alienating most of their existing and potential customers.
• If all goes well the with new App development it will achieve parity with the old one 6 (yes SIX) months after its release. That is not what the users were told at the beginning or what Sonos expected but it is the current reality.
• It looks like Sonos still have the best multiroom solution. I have drawn this conclusion because so far I have not seen the "I'm moving to product X" posts get significant traction.
• It will take some time for Sonos to regain the trust of many of their users and with some that trust will never be rebuilt.
• I'm still looking forward to the new App being completed, stable and responsive so that using it no longer interferes with my listening experience. It remains frustrating, unpredictable and unreliable (but I think it maybe getting better).

These are my personal observations after 3 months. I am sure that others will have a different perspective and maybe disagree with some of what I have said.

Bottom line is that I am just looking forward to this being over.