I did the tidal ABX test, which I prefer since it's comparing FLAC, and the difference is almost negligible. I do hear a slight difference >15k, and I can only year up to 18.5k, but on most tracks it's not noticeable. Also slightly worse transients, but again, only noticable on a few tracks. I also can only hear any of this on HD600s with very, very high volume, which is not how I usually listen to music. I really like this test :)

Lossless is still nice to have though, mostly because I can then rip FLAC files to do good remasters, which is why I happily use tidal (also for a number of other reasons).