Really enjoyed the series -- it's been my late-night fix for a couple of months, and I already miss it.
I am torn on the finale. Although it wasn't flawless in the way I think the 'Breaking Bad' finale was, the actual resolution was satisfying. Dexter's final act, while painful on some levels for Dexter and his loved ones, I thought was one of his first genuinely selfless decisions. I felt his pain and wondered about people in the world with mental issues who can't connect with others in a "normal" way.
I loved the irreverent atmosphere of the Miami PD. I enjoyed the potty-mouth Debra character, and I thought the role was well-acted, although the casting for her might've been better.
I thought Dexter's love interests were really hot, particularly the Rita and Hannah characters.
I enjoyed the writing thoughout, although I think the first four seasons were the strongest.