I signed up for the trial and downloaded two albums in HIFI quality, which is the highest quality that Tidal offers. For comparison purposes, the file sizes for each song were about 3x those of the Google Music ones.
I tested this with my Bose QC25 headset and in my car, which has a fairly high end sound system. In my car I connected the phone via an auxiliary cable to allow the DAC to operate.
I honestly didn't notice any difference between the two in either scenario. Both sound fantastic, especially compared to the same albums via Bluetooth, or on my wife's Samsung S7.
Given the higher cost of Tidal HIFI, and the fact that Google Music also gives me YouTube Red, I'll stick to Google Music for now.