Firstly, I apologize for the length of this review written from a textbox that doesn't understand what and 'Enter' bar does, please continue. I've just watched The 4400 all in 2 weeks. Seasons 1 - 4. And let me tell you - I logged in to this site to leave a review. That should tell you something.
First, if you are thinking about watching this show I AM SO JEALOUS THAT YOU GET TO WATCH IT FOR THE FIRST TIME.
Second, The 4400 is so infuriatingly frustrating at times in the best ways imaginable.
Its characters are so incredibly flawed that we can (at times) forget that some of them are superhuman. Very meta. This vulnerability and depth allows for very three-dimensional characters. We feel sympathy for villains and hatred for heroes. This is necessary but oh so painful.
There are minor loose ends all over the place and the plot-lines are so tantalizing you'll believe that they've found a way to send crack through your DVR. I don't know if J.J. Abrams was busy but why was he not all up on this bitch?! They could have done a bit more with the 'wholeness' of the show had the writers been given a definite chunk of time by the networks instead of being strung along for years.
The series finale left my jaw open and my heart raw. I felt that it ended too quickly; that the writers were trying to wrap things up too quickly; that the characters were moving on too quickly. Thus is the way of the money machine that is the network.
That said, for a series which is mostly about trying to figure out the unknown, causing (and reacting to) fallout and living with your decisions...this is a sci-fi show about aliens and superpowers and good and evil and morality and reality and war and the future and hope...The ending was perfect.
All of these 'frustrators' are so perfect for the content and your enjoyment of the series.
I will be recommending this to all of my friends. I loved it. For me, the 'worst' parts of the show; what others may complain about, were my favourites. I had no idea that it existed when it was on-air. And that is a damn shame.