Vortic, are you new to Battle Network AND GameFAQs, by chance? --- The difference between Fate and Destiny is that Fate is a predetermined course that you choose to follow or leave. Destiny is what you will do regardless.
Blue Moon has fail souls (save Proto/Blues and maybe Wood) and God-awful giga chips. IDK why everyone loves the Bass chip, the RS one is way better IMO.
But anyway, you'd be way better off getting Red Sun, unless you'd like to play the version where only 2/6 of the souls are useable and has nothing that Red Sun doesn't have/get more of/have better quality of, then otherwise get BM.