dfs. Most of the tasks have little defense anyway, so when you have 90+ attack, you're set (especially with pots). Also, +70 def stats is awesome. Ddef is only 5 stat points better with 1 more str bonus than rune defender, not much significance there since I never used it. When I was trying both of them out, I did not notice any difference than with dfs. Just as fast; just as hard; just with quite a bit less def. (yeah, that's what she said)
dfs user for life.