I have had the same experience.
Almost everything about its ease of use and library management sucks.
But the sound quality is truly amazing!!!
I have performed extensive tests, even getting my non-audiophile friends involved and the results were unanimous: hq player is definitely better sounding in real terms.
It's more dynamic, has more slam in the bass, calmer in the treble region, seems to have better spacial and timbral information retrieval and somehow seems to be less noisy.while letting you get more involved in the music rather than the gear used.
This happens in all file types, including hi-res and it is not related to whether one uses the up-sampling or the various filter features or the "convolution engine (which I actually don't use).
JRiver (MC20), Foobar and JPlay are markedly inferior sounding, which saddens me really, as I have already invested in JRiver from back in the MC16 days.
It also seems to benefit from running Fidelizer (or vice versa), a bit more clearly than the other players.
I've also briefly tried an Auralic Aries (which I really liked BTW) and honestly it was too close to my tricked out Windows laptop, when running the hq player on it.
While I definitely need more time with the Aries to extract any reliable or even meaningful conclusions, I would also like to try the sotm mini which runs on embedded hq player before settling on a streamer solution.
The price seems steep indeed and the designer should seriously consider a bare-bones audiophile edition without the convolution engine, optional up-sampling, optional filter section and also the addition of a missing feature: a superior CD ripper (let's not forget that lots of material is still only available on CD).
Then I could propably even live with the sub-standard library integration and the quirky user interface .
I must note that my observations all involve listening through the Lampizator level 4 DAC.
While I don't know if there's some special synergistic mojo happening when the hq player is used in such configuration, I seriously doubt it.