@YetAnotherLondoner: I’ll be following your thread with interest as I’m also looking for alternatives to Sonos. Your requirements match mine pretty closely, but may I ask a question, please? You said “I don’t want a system that’s unusable should Roon go out of business/shut down”: I had thought that Roon (the software) did not depend on Roon (the company) in day-to-day operation - if that’s not the case, thanks for highlighting it. Am I missing something?
In case it’s interesting for you, I’m currently looking at the Naim Mu-So Qb 2 and the B&W Formation Flex, both of which seem to work nicely with Roon from what I’ve read (although both are also somewhat more expensive than Sonos).