Though it’s definitely encouraging to see Parlophone issue a standalone Atmos Blu-Ray in 2023 on their own accord (not even as an SDE shop exclusive!), I do think there's kind of a cruel irony to this particular title getting the lossless treatment while amazing stuff far more deserving of a physical release – like the Joni Mitchell and Grateful Dead Atmos mixes – will probably languish on the streaming services forever.
It sounds to me like they’ve largely kept the stereo mix intact in the front speakers, but – likely by using the object size control – doubled some elements (backing vocals, rhythm guitars, keyboards) in the front height & side speakers. The rear speakers are more-or-less silent most of the time, and the rear heights carry only low-level reverb.
The end result is that, when sitting in the sweet spot and looking straight ahead, the soundstage seems to eerily extend a bit beyond the front speakers (as can often happen with a really great stereo presentation). But as soon as you turn your head to the side, all the sound suddenly shifts toward the front of the room.
I don’t mind the music itself, though I’m not sure when or if I’ll end up giving this another listen (a daring surround presentation and/or better mastering might have helped in this regard). The sound quality isn’t awful by any means, but the louder passages do seem to exhibit that messy 'oversaturated' quality from too much dynamic compression.
The cherry on top is that the TrueHD/Atmos audio was incorrectly encoded with a DialNorm value of -19, so it plays back 12 dB quieter than the original ADM BWF master files printed by the mixer. The Apple Music stream appears to have the intended amount of gain, so I guess I’ll stick to that for future listens. Going with a “5” overall.