Four crazy kids and happy as a clam!
My name is Glenn! Long have I carried Cyrus's hopes and dreams, and now I bear the Masamune as well! Henceforth, I claim them as my own! I shall slay the Fiendlord Magus and restore our honor!
FD is worth a bit more on average, and is the hot game right now. Shopping about i can still find Colosseum for just over $40 where FD i can not. I agree Colosseum will very doubtfully printed again. FD in a couple years will be an old game and may drop to around $50, so i would say it is worth easily $10 more.
Where are you seeing Colosseum for $40ish?