I've tried them all and I've finally settled on Tidal. I won't concenteate on the bit depth/sampling rate/MQA aspects because Tidal (at least in the US) is the only service offering MQA and (despite repeated queries to Deezer), I've never been able to confidently establish what they consider to be "HiFi" streaming. Quboz doesn't seem to be available in the US, even though the company has been promoting/promising a domestic debut for several months. Here's my perspective:
1) Pandora: This service - despite a relatively limited library - offers the ability via the "Music Genome Project" to create interesting playlists based on a sample track of music you prefer. In my case, that's generally jazz of the Davis/Coltrane/Monk etc. era. However, after ~400 tracks, it becomes repetitious and the sound quality is manifestly sub-optimal.2) Spotify: The search function is idiosyncratic (same applies to Deezer) and the ability of the service to generate a non "curated" playlist is inferior to Pandora's "Music Genome Project". The service's music library is extensive but the sound quality isn't satisfactory for most audiophiles.3) Apple: Major problem is sound quality and the emphasis (as with Spotify) is on modern popular music. Given that, the music library is extensive. In fact, it's reportedly the industry leader (and it's about equal to Spotify in revenue generated). The GUI and search functions are adequate.4) Deezer: Sound quality is better than the above listed services, but the search function is frustrating and oftentimes limited. Sometimes, entering a performer's name will yield a "hit" and sometimes not. Entering the track name sometimes works...and sometimes it doesn't. Even using both the artist's name and the exact piece of music won't yield the desired result and inputting the album name works.
5) Tidal: Despite the fact that the main page is heavily weighted to music by the service's owners (e.g., Jay-Z, etc.) and the price for "Masters" quality streaming verges on extortionate, the library is exhaustive, the search function usually yields the desired result, downloading and streaming are easy and it works with Audirvana and other audiophile software applications. Tidal has been teetering on the brink of financial ruin for some time and (per the WSJ and other audiophile indifferent sources) may not be viable...but they've been reporting similarly apocalyptic forecasts for at least the last 3 years and it's still hanging on. Maybe cost ($$$) is too high, though the company justifies this by claims that artists are "better compensated" for their work (does this mean your monthly subscription fee is an act of altruism?)
I would be remiss in failing to mention You Tube. Virtually every recorded item of music has been uploaded there by someone, but the sound quality is MP3 (or worse) and the paid ("Red") service isn't worth the money. Nonetheless, it's an amazing music repository: good for exploration.
Submitted with the usual disclaimers,KAC
