Thankful, it is an up sampling audio player which is highly configurable. For lack of better terms it lays over the top of iTunes and uses the library of files, but up converts the file to be played according to the setup specifications. See the Signalyst.com website, the maker of HQPlayer. I had a guy who builds audiophile servers visit my home. He offered to set up my Mac Mini with HQPlayer, and an hour later we were listening to my Mac Mini with HQPlayer. It may not be a pretty interface, but wow does it vitalize PCM files.
He also told me about Splashtop, a $5 app for Mac that we installed onto my iPad. Now I control the entire Mac with the iPad. I open up Splashtop, then open HQPlayer and boom, it's off and running! I also can run Sonos via the Splashtop software. Intoxicating control and convenience.
I think I've taken Sonos about as far as it can go. I think a trial of Tidal is next.