It's interesting that the unit is already available at Best Buy.
I'm not so keen on the looks of the handheld remote and I would need to see the on screen UI. It seems that they are relying heavily on voice control.
One does need a subscription.
I don't how multi-room is handled. Possibly it would be one single room system per room.
If you read through the FAQ, search results have a priority based on setup order and input port. It was not clear to me, for example, if one searches for an actor and the cable box is has a higher priority than a ROKU, that search would find the actor on ROKU. And there could be confusion over which device has priority. One FAQ entry indicates priority is associated with input port (HDMI1 is higher than HDMI2), but another FAQ indicates priority is associated with order of setup and one would need to setup again after a new input device was added.
Sonos integration seems limited to Volume and Mute, but this is probably not a major limitation since Sonos can also be controlled with Alexa or (soon) Google.