It peaks at the end of Ep5, imo.
It could have, should have, probably ended a couple of eps after that. You'll see why... it sort of jumps the shark and ditches what made it good towards the last 3-4 episodes and it takes a turn that isn't for the better, imo.
Still a good show.... I just felt the twists and stuff in the last 3rd of the season was unnecessary and made it worse.