Instruct: Classify Amazon reviews into positive or negative sentiment
Query: 3rd installment of a smart, intriguing sci-fi series!

I'm usually not inthralled with science fiction but this series has just the tight mixture! I'm now on the fourth season and am already anxious about its eventual end. It has great writing, acting, and suspense. Love the actors and I am very surprised that the show has not gotten more notoriety.