The first good mark it has is that it's not annoying. When characters do things, it makes sense that they would do them based on their apparent or possible motives, capabilities, and perspectives. Unlike, say, Heroes where enjoyment of the series is dependent on how good you are at overlooking the writers' laziness.
On top of the fact that The Sarah Connor Chronicles isn't annoying, it has positive aspects (boy, I'm just a push-over, ain't I?). Summer Glau is excellent, and even though Lena Headey doesn't quite capture what Linda Hamilton did, she's still very good. The show has the pervading gloom that naturally comes from characters who know the world's heading for a terrible fate. And I like how Summer Glau Terminator is not obligated to follow John's or Sarah's orders. There's the constant threat of her killing someone innocent or of her allowing someone innocent to be killed.
The guy playing John Connor is pretty milquetoast, but I guess you can't have everything.
I went for a candy run last night. A two dollar bag of liquorice and a dollar bag of Atomic Fireballs. It's weird the things I'm in the mood for these days.
I see the Atomic Fireball was invented in 1954. Now I feel like I'm snacking on something Oppenheimer developed.