If the rewards in Advance is much better, than doing Advance seems better. I didn't look at the rewards, nor do I do these missions.
Kill speed is only important if you value experience over rewards.
By rewards, I mean like potential Darkness Cylinder or something like that, not the exp/gold reward.
You were probably interpret my mentioning of "rewards" for that instead of the rare item drops at the end of certain missions.
Also, I have no problem killing hard mode monsters at all, although that is my own problem... or lack of it.
Ehh, my mind is more focused on the exp, not the rewards really since they're pretty rare. Believe me, if I wanted some good rewards, then I'd definetly do harder levels.