Regarding the show, the actress who played Sarah was pretty good even though she didn't look nothing like her. That didn't bother me too much, characters change all the time. Hell, if the strike didn't post-pone the new Justice League movie, we'd have 2 different actors playing Batman and Superman at the same time as their movies are coming out. Plus there's Smallville as well. So I didn't have as much of a problem with that as I do some other stuff.
I HATE both Terminators. They're so lame compared to the other Terminators, even counting T3. And yes, I'm counting Summer Glau in that. I did like some of the things they did with her model: being a new unidentified one, being different from the other terminators (more personable seemingly), being John's body guard and enrolling in school with him, plus she's cute as hell. I really wished they would have made her a love interest for John rather then a terminator. She played a similar character in Firefly/Serenity, so it'd be nice to see her do something different.
Regarding the T3 ignoring, would it have been possible at all to tie it in? I don't really remember T3 that much, but didn't Sarah die in '97? They set it in '99 with her still alive, couldn't they have just done it a couple years earlier? Did they make John the same age as he would of been after T2? Didn't follow things that closely. I liked how they did tie in her cancer (a little homage to T3) and how they jumped over her death in the new timeline. I think that would have been a pretty cool way to still sorta tie in T3 but basically wipe it out. Don't have a problem ignoring it though, but I thought that would have been pretty cool.