Differences:
-Euro firmware (no more freelauncher)
-Wind-ups 0.99 (copy, rename, delete + some more functions)
-Possibillity to create your own boot-menu
-Possibillity to create boot-files so you can launch different software depending on the SMC you use (straight into os9xgp with one card, straight into the MP3-player with another). If you only have one SMC you could use PacRom for that.
But:
-Aquafish loads slower (because it reads the bootfile from the SMC ?)