Speaking to Oorjit after killing 100 Crystalline Wisps:
Oorjit tells you, "Excellent work in your hunt. We'll find your reports very useful."
You've earned 20,000,000 experience.
Oorjit tells you, "Congratulations! You are now truly a Wisp Whipper."
Speaking to Oorjit before the timer is up:
Oorjit tells you, "It's nice to see that you are so anxious to continue the hunt, however I can not issue another hunt at this time. Please return to me at a later time and I may be able to issue another hunt again at that time."
There are far more wisps in the dungeon than on the plateau. For a mage it would be faster to use ring spells in the dungeons than kill outside on the plateau.
Lower-level archers have an easier time on the plateau.
Lower-level melees can have a much easier time in the dungeons thanks to the walls.