I had heard mixed things about this, plus given the recent series, I was concerned about the studio I thought that produced it, but it turns out that both opinions were incorrect. The movie is actually a lot better than Terminator 3. It had a few flaws, but using the 'movies are fun' argument that justified Transformers 2: Robot Testacles for earning $200 million, I think we can cut this one some slack.
The movie is basically about how John Conner actually becomes the head of the Revolution. It has a lot of action and an interesting side plot about a man who mysteriously shows up who was in suspended animation and then appears naked out of nowhere who makes a significant difference as to whether the good guys succeed or not.
I liked it, but it had a few problems.
One of the biggest comments I've heard is how easy it was to sneak into the complex. Yeah, well, apparently a lot of other reviewers are moronic, because it is VERY easy to sneak into the main complex of the bad guy when they want you to.
Now, the 'why pick a guy from 1993 who is going to stick out like a sore thumb to lay your trap' is another criticism I hear a lot about this movie. Actually, the 'its so dumb it just might work' defense seems valid to me. I honestly have to wonder just how much proof you'd have to offer someone if you claimed to be from the future and that you were trying to alter the timeline to prevent a disaster. I'd bet that it wouldn't take much proof and that there would be an awful lot of people that would totally fall for it. Plus, maybe Skynet didn't have a lot of bodies lying around when it first started, so it picked the one with the most data lying around.
Now some things were lame.
Skynet is just stupid. The humans always do the best they can with what they have, sometimes against hopeless odds, but Skynet is aware of all the time paradoxes (hence its desire to kill the guy who is going to be John Conner's father) but it doesn't care about temporal paradox and just goes ahead anyway. It also pulls a 'join me, and together we shall rule the galaxy' with the cyborg guy.
Not yet once has anyone tried to make the paradox work via ignroance. For example, in T3, John Conner is revealed in the future to be killed because he was a moron and trusted a T-800 too much. Why can't he just program the robot with false info and send it back that way to maintain the timeline, and then shoot any @#$@#$@# T-800's that suddenly try to become friends with him?
One can hope that might happen, but I'm not holding my breath.
The good news is that at this point, we're entering new territory with these movies. We don't need to keep wondering if Skynet will send yet another crappy robot back in time, because we KNOW it has to happen to avoid temporal paradox.