Did some quick short tests Sonos Arc vs Kef LSX (LSX prob need a bit more breaking in still) but, so far...
Stereo music (Spotify) - It's not a contest, the Kef's are in everyway better for stereo music. Kef's big wide lifelike soundstage, bass/mids/highs all rich but tight(though I'd question if they were that much better than my Dali/Denon £400 combo - but you do get a much smaller less cluttered set-up). The Arc the sound varied depending on the track. Sometimes it sounded ok to good, other times it sounded like the music was being piped through a metal biscuit tin. Soundstage much more enclosed. But it was never unpleasant. I know, stereo speakers beating soundbar in stereo music contest shocker. But the take home is if music is a high priority you might want to get some demoes first .. though the Arcs are fine for casual listening and background music. Relative scores (not absolute)
Kefs 10 / Sonos 6
5.1 TV (Sky DD) - Watched Succession (great show) the Kef's did a good job with PCM audio, nice full wide sound, clear dialogue, good with soundtrack. But the Sonos were better. Dialogue, the Arc's knock it out the park, it's like the dialogue is stuck to the screen where each character is and is a level or two clearer than the Kefs. Also ambient "surround" noises much better seperated than vs Kefs, creating a more realistic more engaging sound (though "surround sound" is a massive stretch - at least in my room). Soundtracks sound as good as the Kefs - I'm assuming as mixed in 5.1 they don't have the 2.0 to upmix 5.1 issue which created a mediocre stereo performance. (Might have to checkout Tidal's Atmos music selection)
Kefs 7.5 / Sonos 10
Oh and zero bass issues with the Sonos, while it wasn't as tight and agile as the Kefs it matched them for output and extension, easy. I expect the Rtings score to go up considerably on 12.0.1 re-review.
Currently leaning towards building the Sonos system to 5.1 and getting some cheaper bookshelves for the study for when I want to listen to music (if I was flush I'd keep the Kef's but some £400 actives will likely give me 80% the performance even if they aren't so small and sexy) Planning on running some more tests this weekend with more cinematic tracks, Atmos etc. to confirm initial findings. Nerd level fun or what