This movie was not as bad as I feared. From the reviews and analysis that I'd read, I thought it was going to be an unintelligible mess. Christian Bale as John Connor was going to show up in places he wasn't meant to and be useless and Sam Worthington (as Marcus, the part Bale was wanted for) would be the heart of the story. In fact, John Connor was an important part of the story and helped move it along. This much was right: Marcus was the heart of the story. Oh, and it is an unintelligible time-travel mess.
You've got time-traveling John Connor trying to operate in the future based on Sarah Connor's semi-prophetic cassette tapes from the past. He should have been much more concerned with the present. You've got time-traveling Marcus awakened in the future after being lost in some weird government cyborg experiment for fifteen years (or is he?). And you've got time-traveling Kyle Reese, who's supposed to go back in time and be John Connor's father, doing his "I Am Legend" schtick in a wiped out Los Angeles as "the resistence". And you've got SkyNet an AI we can only make films about leap-frogging about forty or more years of technological advance in only nine to gain real artificial intelligence, advanced robotics and metallurgy, and some pretty cool flying machines.
It's a mess. Yet, it's all done with such polish and aplomb that I was again willing to turn over my two hours (including trailers) and $10 (!) and come out the other side glad I did it. It's not a science fiction film I could recommend to a non-fan, even one that likes action. It's not an SF film I would place anywhere near the likes of the original Terminator, or Alien, or Blade Runner. But it wasn't bad.