Spotify: how good is high quality streaming?

Is there an actual difference between high and normal quality streaming on Spotify? How does Spotify high quality streaming compare to CD quality?

I've been looking all around to find a decent review that shows me how good is the quality of Spotify's "High quality" streaming. No luck, so I'll do one.

CD RIP (flac)

This is the spectrum and wave of the original, 1996 CD version:

spectrum, CD version
spectrum, CD version
wave, CD version
wave, CD version

320kbps MP3 from CD RIP by ffmpeg

spectrum, 320kbps MP3 from
CD
spectrum, 320kbps MP3 from CD
wave, 320kbps MP3
from CD
wave, 320kbps MP3 from CD

Spotify high quality (desktop) streaming

( Recorded with audio-recorder[^3] into flac. )

spectrum, spotify high
quality
spectrum, spotify high quality
wave, spotify
high quality
wave, spotify high quality

Spotify normal quality (desktop) streaming

spectrum, spotify normal
quality
spectrum, spotify normal quality
wave,
spotify normal
quality
wave, spotify normal quality

Conclusions: high quality is still not CD, but is far ahead of the 320k MP3 output of ffmpeg.

(Oh, by the way: this entry was written by Peter Molnar, and originally posted on petermolnar dot net.)