I spent a few hours listening to the same songs on Amazon Music HD, Tidal desktop and Amarra Luxe desktop, all running on macOS Mojave 10.14.6. It was a laborious process as I made sure I only had one of the apps open at any time to stop exclusive access to my Topping D50 DAC becoming an issue, plus I had to check the settings each time I opened one of the three apps to make sure that the settings hadn't changed. Anyway, a side interest to me was Tidal have updated their app twice in 24 hours!
My objective was to see which app produced the best sound to my ears, as that's all that matters to me.
In order of 'best sound quality' to my ears:
1. Amarra Luxe desktop for macOS Version 4.3.510-208 - a very poorly written app in terms of UI and adhering to macOS app standards - seems to break every standard there is for macOS apps BUT...sounds simply delicious. I use Amarra Luxe to play my Tidal playlists so the source files are streamed from Tidal. The app produces a thoroughly engaging representation of the music. Rich timbre, wide sound stage, beautiful separation of instruments. It's hard to see how the sound could be bettered on my current hardware.
2. Tidal desktop app for macOS Version 2.7.0.5 - not far behind Amarra Luxe, to my surprise! A lovely UI and some really useful features to discover new music. A glorious representation of the music, deep and wide soundstage, a full-bodied richness to the tracks. It's progressed a long way from a year ago.
3. Amazon Music HD for macOS Version 7.8.2.2104. UI-wise it's probably where Tidal was a year ago so will improve with new updates I imagine. Unfortunately the sound, possibly due to lack of exclusive access and lack of overriding the OS mixer and volume control, was a little flat and anaemic compared to the other two apps. It's a pleasant enough sound but lacks engagement - better suited to background listening as far as I am concerned. I'm really hoping that Amazon can rapidly update this app as there's no technical reasons why they cannot make it sound as good as the Tidal app. I'm guessing it's a step up for Spotify users, but it's a couple of steps down from Tidal at the moment. Needless to say I've set up the reminder from within the app to notify me three days before my free trial ends.
Thanks nice review! Substitute Audirvana+ for Windows 10 for Amarra Luxe and your findings agree with mine. You got me curious about demoing Amarra Luxe but when I investigated it only plays up to 96 kHz while Audirvana also does 192. There is a lot of 192 content on Qobuz.