Secret sauce is source control. You can get a matrix switcher and come up with your own controls but smart remotes like URC and Control4 are way more expensive and IMO are less reliable.
Surround speakers need a priority switch if you want matching amp profiles in the home theatre.
I have in ceiling speakers each pair connecting to a sonos amp. Outdoors, in garage, etc. It’s great - for me. I have Play:1s in bathrooms without mics and it can all sync.
Guests can also control it via phone.
What pisses me off:
- Lack of auto firmware updates at night
- Latency with external sources unless you use a sound bar, maybe fixed with port? The connect sucked
- Spotify premium required
- Cost