Season three made it clear that they had just exhausted all of their creativity. Filled almost entirely with plot holes or plot convenience, the second half of the season was clearly just an attempt to bring the whole thing to a close. imo they could've wrapped it up in s2 without anyone missing anything.
That being said, I very much enjoyed the first two seasons. The world building in season one was good, and set up for season two very nicely. I feel that the concept they chose was very limiting for how many episodes they had, which lead to season three's disappointment.
TL;DR watch up to season 2 and then stop. You'll be better for it.