I just picked up an Airport Express this weekend to try in place of the Chromecast, just because I'm so sick of using the Bubbleupnp to stream Tidal to the Chromecast. Man, that app sucks. All I want is to use my iPhone to stream Tidal. And currently the only way to do that is over AirPlay. The Airport Express is a cheap way to get AirPlay. Eventually Tidal will get casting support for iOS, but until then...
After a few days of listening, I can say that I'm impressed AND disappointed with the Airport Express. I'm impressed because it has a killer DAC onboard. I A/B'd it with my Emotiva DC-1 DAC, which gets very favorable reviews, especially for it's price ($500) and there was very little difference. The DC-1 might sound a little better, but I doubt I could pick them out blindly. One could run a 3.5mm analog cable from the AE directly into an integrated, or even simpler, run it directly into the amp like I did, because it puts out a line level voltage and not even mess with a separate DAC and probably be happy. I'm disappointed because I was plagued with constant dropouts from AirPlay. Now, this won't be everyone's issue, but I'm forced to run my AE wirelessly. You can plug in an Ethernet cable, but I'm not able to do that. So it connects wireless to my main router upstairs. The problem is that I never had issues with the Chromecast (also wireless). It would grab the track and stream away with no issues.
So I'm back to using the clunky Bubbleupnp app on my Android tablet with my Chromecast until Tidal can finally get native casting for iOS.