I'm a huge fan of Terminator. The first one gave me nightmares when I was a kid, the second was just as good, the third one, well... Salvation really disappointed me at first. I just can't see Bale as Conner, not that he doesn't act it out nicely; he just doesn't work for me personally.
This film had to grow on me because I guess in many ways I had my own thoughts on filling in the blanks from what I knew of the story from the first two films. I guess it's like reading a book and then seeing the film only to find the lead character wasn't how you pictured him to be...
The directors did a good job on refreshing the story. No it doesn't follow the same foot print of the first one, but if you understand physics and space time continuums it can't. In Terminator 2 Arnold, John, Dyson, and momma Conner "stopped" judgment day from happening and changed the future (The future's not set - no fate but what we make for ourselves) and then in the third one we learned that judgment day was never stopped only postponed.
Watching the special features really helps me understand the directors mind and vision for the film. It's easy to judge a film based on your own ideas and say the director did a terrible job, but once you see all the hard work and thought put into it, you just can't judge it so harshly. Once I understood why the director did some of the things he did, this movie was better to watch. They did a good job of filling in the blanks. I enjoyed actually getting to see Terminators from a perspective that the other films have never shown before.
I give it 4 stars out of 5 because on its own (not in comparison to) it's a nice addition to the family of films.