Season one was very good. Engaging, interesting story, shocking elements, complex issues and acting was very good.

Second season was alright, not up to par with the first season.

Third and fourth seasons I can't really remember what happened, none of it was particularly memorable.

I watched the fourth season whilst in labour and the labour wasn't the reason I can't recall what happened. It just dragged on, storylines going everywhere with a random death at the end.

Watch the first season but stop after that.