A few annoyances:
-- Mobile app constantly logs out, forcing you to constantly log back in.
-- LastFM scrobbling is screwy, seems to randomly pick tracks to acknowledge and just passes on the rest that you listen to.
-- Airplay is a pain. You have to select it in preferences inside the desktop app and if the connection drops for any reason, TIDAL defaults back to the internal speakers. Spotify seems to just follow the system output setting.