Didn't anyone notice that when John asked 'tinman' what model she is, she didn't answer? that creates some interesting possibilities for the future, she might not actually be a Terminator (Human cyborg with Terminator parts for example)...
Timetravel:
Often time is represented by a string, time travel is a loop in that string. In my opinion the Terminator franchise is a couple of miles of string wound around a finger, which is a good thing imho. I see the Saraha Conner Chronicles happening after T3, or even after T4. Just enough has changed for another loop to happen.
Terminator:
He's like Arnies illegimate child, I expect him to say "I'll be back!" at any moment ;-)
Movement is very T1 like, even some of the earlier fight scenes (shooting up a bunch of police and their cars), very nostalgic. The fights between the Terminator and 'tinman' are, to much the same imho, how long can throwing each other through walls and floors stay interesting (once).
Sarah:
Is still going to die, just because you time travelled doesn't mean cancer isn't going to happen. The actress playing Sarah is good enough imho for the role. The series depicts her as a bit more human and less certain, but at the same time a bit more insane ("I don't even know what i'll do!")
John:
A teenager with the luck of the devil, I like how he's depicted, I think the actor is good for the role. I like the way how he's innocently accepting the 'tinman' as a friend, just like in T2. Although I like the looks he sometimes has "What was I thinking sending her back...".
'Tinman':
Excellent choice for a female 'Terminator', loved her in Firefly/Serenity, I'm going to love her in this role as well (she does the inhuman part so well, would love to see her as an archvillain). Liked how she imitated the female ganger, found her ruthlessness refreshing (I just hated that they had to show she was right, would have been so much better if this wasn't revealed).
Overall:
I very much like the series, I hope they don't cancel this! It motivates me to watch the movies again.