Blue Note Records now has an app on Spotify and it is quite nice. The audio quality is suprisingly good, even on the free version (if you can suffer the ads). Supposedly the "Premium" account will stream at 320 Kbps if the file is available at that bit-rate and you enable "High quality streaming" in Preferences. I've just scratched the surface and I don't know how much of their catalog is available, but it seems pretty extensive.
I wasn't impressed with Spotify when they launched, but I am now.