I love all the characters although we're kind of frustrated by a few little changes like the fact that Sara died of leukemia in 1997 but the show's pilot opened in 1999.
They actually addressed that in the show, though maybe the dates were off. I don't remember when she was supposed to have died according to T3 but Cameron tells her she died of cancer and they skipped ahead in time to "skip" her death. Then she goes to get a checkup and the doctor tells her shes fine. Also, when they made the show they said they were skipping the events of T3, so just think of it as a sequel to T2.
While Summer plays the terminator very robotic, I think its perfect for the roll. I remember after the pilot people were saying she was a terrible actress, but she's doing it this way on purpose.