I watched most of this series on tv then got the dvd to rewatch it and catch up on the pieces I missed.
It's an excellent series, suspense and sci fi mixed well together in a tale that spans the globe and the years. And if it has one strength to shine above all the others for me, its the characterizations. The show goes to great lengths to show the mighty falling at every step of the way. The president, young and idealistic, slowly being broken down and turned into a paranoid and desperate man who will do anything to protect his country. The leader of the aliens, a woman who starts off near saintly, torn apart by events including the death of her son and the unexpected approaching destruction of her race, turning into a mass murderer. Yet even as it brings the mighty down it raises the humble, with an assassin being slowly transformed into a hero, a paranoic head of security being shown as paranoid for a reason and even learning to trust. The acting is superb.
There are however two weaknesses for me. The first is the unecessary way the plot jumps through time periods.I don't mind the odd flash back, but at the beginning the show is all flashbacks, and I found myself constantly being jerked out of my comfort zone as I tried to work out where and when I was. It interrupts the flow of the story.
The second are some strange plot hole issues. (Warning some spoilers ahead). First the pilot of the plane. Since any plane and any pilot would do why would the bad guys kidnap the daughter's of an alien on Earth to do it, and in so doing create a mess for themselves? It seems contrived and unecessarily complicated, though of course if it hadn't happened, the story's main character and plot couldn't happen.
There is also the issue of the defenders of humanity, who it turns the initial bad guy is one of. I don't have a problem with a secret underground resistence opposing an alien threat, that's fine. I do have a problem with them fighting an alien race with uber technology, with mystic knowledge, ancient scrolls and moving pieces of stone representing people(?) on a strange stone tablet of future events. Its just wrong.
And then there's the major plot hole. When the alien's go mad and start planning the death of humanity, its all so that apparently the Earth will have room for their two and a half billion people. A strange reason but still a reason. Then right at the end (Major spoiler), they bring their entire world across and set it up somewhere out there in Earth's orbit. If you can do that and your only danger to your world was that the old star was going supernova, then why do you need the extra room? It sort of makes everything that has gone before, completely redundant.
Still, other then those issues, this is an excellent show. Taught, tense and a walk into the unknown, exactly as it should be, and I highly recommend it to anyone who likes a good alien romp, a thriller and a mystery.
Its a pity that there will be no second season.