The U1 Mini sounds like it would potentially be a nice fit for me! I love the fact it shares the same design features with the other Lumin streamers/Dacs as they are the most beautiful on the market today imo.
However, one of my biggest concerns with any streamer is constant connectivity issues and frequent dropouts, as Acaciaavenue and others have experienced. My time is limited for at-home listening, and constant disconnecting/reconnecting would really suck the fun out of it. I recently upgraded to the latest Verizon Gigabit modemn and mesh network extender so I will mess around with that a little this weekend and see how stable it is. Luckily, if I did go the U1 mini route, it would be running on the mesh extender, which isn't incredibly far from the modem. Acacia, thanks for pointing out the D2 is not Tidal connect compatible, as that's a bit of a deal-breaker for me. I saw Lumin listed on the Tidal connect supported devices page and just assumed being the D2 is a newish model it would have been supported. It makes me wonder if the U1 Mini or any Current Lumin Devices will be compatible with Spotify Hifi once that's officially released.
Spencer, I most certainly plan on phasing out airplay and Itunes classic out down the line once I'm settled in with my new system. Keep in mind that a lot of the non-streaming source material I listen to is 320KPS mp3 quality, so I'm unsure how much quality degradation I'm experiencing using airplay. This is one of the reasons I plan to integrate a transport eventually so I can rebuy a lot of the music I listen to on CD that isn't available in higher quality digital formats.