I noticed immediately something sounded off, the dynamics were flat. I thought it was in my mind but I'm still hearing it.I have and found the sound quality to drop drastically. After turning on debugging and saw that it was no longer doing DIRECT I/O instead going through the MIXER and being resampled. This was fixed by setting the DIRECT flag in UAPP Hifi Audio settings. I do not use Spotify directly as a source for apples to apples comparison though.
Overall I like what Oreo has done...but it has its quirks......and the aspect ratio of the visibility screen seems to have changed with Android 8 from 7.
Is it possible to revert to 7.0 by 'restore factory settings' reset? 8.0 is a nice upgrade but I only use this for audio and 7.0 just sounded better to me.