I subcribe to rdio. I'm evaluating Spotify. Depth of catalog is important. But for say, Tom Johnson, both services have four of his albums. Rdio also has An Hour for Piano. Spotify has Rational Melodies. I'll call it a tie. User interface is better on rdio, though.
Just Outside posts about a new Tom Johnson recording and says he loves An Hour for Piano. This minimalistic piece could be considered "clunky," but in fact I also like it, length and all.
"A trance music piece made up of repeating 4/4 cells in which an absolutely steady eighth-note motion predominates" (amazon)
"But in An Hour for Piano there's really nothing you can memorize because the returns of former figures are too unpredictable, and there's almost no measure more or less difficult than another." (postclassic)
Andy Lee has MP3s of his performance of the work. (walkingstick)
From the program notes: "It is important that you try not to allow the program notes to distract you from concentrating on the music. They are intended to increase your ability to concentrate on the piece, and not to distract from it. If you find that reading the program notes does not increase your ability to concentrate on the music, you should not read further at this time. Perhaps, at some later time, you will find that reading the program notes will increase your ability to concentrate on the music." (dram)