With my Linn streamers, Tidal HiFi sound quality is not better than my own CD rips streamed from my server. When comparing FLAC vs. FLAC for relatively new music which hasn't been remastered over and over, the two are often indistinguishable. But when I perceive a difference, it's always small and in favor of my CD rip. I have heard that Universal applies audible watermarking to the files they provide to streaming services. Perhaps other major labels do too, and that is the reason for the perceived difference in sound quality. Or maybe there is some lossy compression going on to save bandwidth on slow connections or at peak load. Or it's all in my head. Or something else.
For older music, especially classic jazz and rock albums, and old orchestral war horses, I think music streaming services like Tidal are a crap shoot sonically because these albums have been remastered countless times and you don't know which source is being used for the stream. In some cases, it's pretty obvious that the Tidal stream is sourced from a different remaster/re-issue than my CD, and the Tidal version is clearly superior. In other cases, I can tell the Tidal stream is sourced from a remaster made during the loudness wars, and it's considerably worse than the version I have on CD.
HT: Dynaudio C2, Contour S CX, 2x BM14S, Aperion surrounds, Simaudio Titan, Marantz AV8801, Oppo 103, Linn Majik DS, and a Pioneer Kuro
Stereo: Dynaudio Focus 160, Simaudio W-5 LE or Luxman M-600A, Linn Akurate DSM, 2x Rythmik F12G
Other interests: motorcycling, skiing, being active