If, hypothetically, there were no set bonuses, Keeper's Staff is better than Mirage Staff, correct? I mean, Keeper's Staff has everything Mirage has PLUS higher DPS AND higher spell damage (due to a higher weapon damage). In essence, if there were no set bo nuses, Keeper's Staff would be every superior to Mirage Staff.

However, the Mirage Staff contributes to a set bonus, which is good enough that it is okay to sacrifice the DPS bonus of the Keeper's.

So, my assumption is that I should use Keeper's Staff if I don't have everything else for the Cosmos set, but if once I have the rest of set, I should switch over to the Mirage Staff? Am I correct?

(On a related note, for Pure Int mages, is switching to Cyber worth the set bonus sacrifice?)