I don't remember what the reward was, beyond completing another part of your journal. I don't think it's anything fantastic though.
You'll still be able to do the repeating quests when everything else is said and done, but a better reward is to beat the game and try it again on Tyrant Mode. It's tough though, especially in the beginning.
And I second all your praise and gripes. One thing to note: if your guys get stuck, you can keep pushing forward, and eventually they'll respawn back in your party.