It didn't make much sense to kill young cgi john Conner in the first couple of minutes. The woman Terminator makes poor decisions such as throwing the metal rods at the Terminator and not the engine. Well that needed to happen so Sarah could show up. The characters are boring, react like nothing bothers them, poor acting mostly. I mean she has to protect the girl, then there is a scene where the girl is out alone comes back to a locked motel room.
There are some good bits, I liked seeing john Conner until he was killed, I like Sarah Conner of course and Arnie.
Arnie and Sarah both added some fun and the best lines.
The young girl Dani is the main one letting down the whole concept. Her acting isn't that great, and kind of a unbelievable character really.
The cgi looked more fake at times.
Like someone else said it isn't for the fans. I'd say the order goes t1 t2 t3 and salvation.