Wow. Well, what can I say? I fell in love with the style, action, and mythology of this series from the start, and the characters are those whom I wanted to know more of and cared about. The first episode for me is what drew me in, wanting to know what exactly was going on, and I am a fan of reversed or out of sequence chronology. However, I agree with many others that the overall story arc is, well, saddening. The ending in particular may leave you feeling a bit empty inside and wishing things could have stayed the way they were 'round about episode six.
This is one of those rare series that I would like to watch again but don't dare to at the same time. It is beautiful and haunting but depressing as well. It felt a lot like reading a Ken Follett novel. Bad things continue to happen to good people, and you keep thinking and hoping that things will get better, but they don't. Still I'd certainly recommend this series, just so long as you can offset the tragedy with a healthy dosing of something a bit more upbeat.