I just did this quest today, and I have to say, I really love the immersion it brings. Very characteristic of the Old Stones, very impressed. However, I was rather put off by the reward at the end of it.
Considering the nature of the environment (without giving too much away) and the enemies, particularly the boss, it has trouble standing up to much more impressive lower level supply quests in the same caliber, such as Beetles or Kobolds. I think perhaps a small boost in the amount of potions or nifty goodies it gives would benefit the quest a lot.
It is one of my favorite quests hands down. I LOVE it. Maybe my favorite quest simply for the ambiance and creativity.
The reward is a bit low though.. I always took it for one of those "xp not gp" kind of quests though.
you also still have to deal with the old stones curse in the quest, so that is added difficulty for new characters to!
The rewards are random! I did it the other day, and got a very good payout in the end.