Thanks for the comments, @jyoung and @slembcke!
@jyoung: Was it a success, because the file size/quality -ratio was good or because it wasn't cpu-intensive?
@slembcke: Do AAC and Ogg provide better file size/quality than MP3?
Here are the results from our tests (the same sample is used for each and everything is 16-bit):
AIFF - 11kHz - 526 kb (quality: 1/5)
AIFF - 12kHz - 572 kb (quality: 2/5)
AIFF - 22kHz - 1051 kb (quality: 4/5)
CAFF - 11kHz - 531 kb (quality: 1/5)
CAFF - 12kHz - 577 kb (quality: 2/5)
CAFF - 22kHz - 1057 kb (quality: 4/5)
MP3 - 64kbps - 124 kb (quality: 3/5)
MP3 - 80kbps - 124 kb (quality: 3/5)
MP3 - 96kbps - 148 kb (quality: 4/5)
MP3 - 112kbps - 172 kb (quality: 5/5)
MP3 - 128kbps - 196 kb (quality: 5/5)
As you can see, since the highest AIFF/CAFF measures to about the same quality as the 96kbps MP3, while the MP3 is only a sixth of the AIFF/CAFF file size, to us it would look like MP3 is the better option. Do these figures look sensible to you guys?