CREAINNOVATOR  Excellent. I tried this with classical piano music, jazz and rock. I found it easy to either use the pre-sets or set custom values. It made the sound on my Bose speaker system connected to my PowerPC G5 audibly and significantly better. With the $12 promo this is awesome. Highly recommended.  
(Version 1.1.3)

CREAINNOVATOR  I have this latest version and have been a user since version 4.3. I have had no problems running it on OS X 10.4.5. The programme has only become better, more codecs and a little bit faster. It is assuring to know that the developers continue to develop and upgrade the programme. I expect that if a new iPod comes out with different screensize (e.g. video iPod), the developers will add this to their compressors etc. A bit pricey, but the software is reliable.  
(Version 4.5.3)