I’m surprised at how good MP3 can be. I’ve just tried mp3ornot.com, which lets you do ABX tests between 128 and 320 kbps MP3 files. After getting one correct answer out of three, it was obvious that I was mostly guessing.
What’s surprising is not really the bitrate (I have previously ABX-tested Vorbis q2 (~96 kbps) and found it to be almost transparent); it’s that MP3 encoders have gone a long way since the last time I tried them. I guess most of their notoriety is carried over from the Napster era which, come to think of it, ended around ten years ago.
On a related note, MP3 and H.264 share an ironic trait: both are patent-encumbered, yet the best encoders for for them are free / open source software (LAME and x264). The difference is that MP3 is inferior to pretty much any of the other formats in use today.
