I haven't tried streaming to my system, but from the computer to a presonus audiobox 22VSL to Sennheiser HD650's, I think Tidal might sound a smidge better, but certainly not enough or definitively enough to make an extra $120 a year worth it.
After a little more experimenting it's hard to say that Tidal sounds better at all since it sounds like Tidal is just plain louder (by a little bit, but noticeably so) given identical volume settings. After level matching by ear, I'm not sure I hear any differences at all through the headphones.
I don't know, maybe my ears just aren't discerning enough or I'm picking the wrong songs, but I'm not seeing where Tidal is worth the extra money per month over spotify, even on the main system.