Hopefully this may help some with questions, just some of my impressions.

Setup: Sonos Arc with Sonos Sub, and 2 play ones

1.) In a larger open room, which is not ideal, the Arc sounds fuller and more clear than a Playbar, which in turn is fuller and more clear than a Beam tested in the same space. Even in an open room, sound is fairly immersive and has plenty of power and punch with the right movie/audio source.

2.) Arc performs much better in a smaller room with more traditional 4 walls, since Atmos has more surfaces to bounce off of. This is also true of the Playbar and Beam, they sound better in a smaller room due to the obvious acoustic benefits vs an open room.

3.) For music, it's better and has a bigger sound stage than the other sound bars, but is noticeably less impressive than a Sonos AMP with a pair of Bowers and Wilkins 685 speakers in terms of soundstage, audio quality, etc.

4. Likewise, for movies - the AMP with the BW speakers in home theatre mode definitely has some benefits vs the Arc, of course no Atmos, but it feels a bit more punchy and sounds like glass seem more defined and realistic.

5. A note on TVs: The Arc worked perfectly with my LG C7, showing Atmos properly in the Sonos app. With my Samsung QLED TV from 2018, Atmos does not show up in the Sonos app, but it still sounds great with what I assume is just regular 5.1

6. I also have tested a Bose 700 with their 5.1 setup side by side. The Bose has very clear dialog for TV and movies, slightly better than any of the Sonos options, even with the dialog assist on. BUT in terms of an immersive 5.1 "surround sound" experience, IMO the Sonos is much better - even the Beam I think is close, the Playbar slightly better, and the Arc significantly better.

7. Keeping the Arc on the LG TV, and on the Samsung I'm debating where to keep the Playbar or my Amp with BW speakers.