Well Debian (mostly because of Ubuntu) has one of the largest libraries of applications. However, Pandebian (in my opinon) makes SuperZaxxon the best OS for the Pandora.
So to really answer your question, not much. Its more if you prefer it or your enviornment requires it. If you needed Slackware you would probably already know that you needed it so fo you I would guess that SZ does just about everything.