The multiple story lines (urban warfare, the FBI investigation, and John's high school life) are kept reasonably interesting injecting charisma where necessary and playing to expectations when it has to (there'll be, I think, a terminator-at-the-prom episode). If anything, the high-speed pacing leads me wanting more of some of these lines. That's a good thing.
It surprised me in several cases. An established bad-ass human runs afoul of Glau's lethal Cameron cyborg? He doesn't even get a death-scene: he's just done ("You have no idea what you're walking into," says a character to the bad guy's controller). The FBI assault is shown with the goofy but still somehow highly effective perspective of various armored SWAT guys falling into the complex's swimming pool--shot from below we see their blood spread out into the water.
The show's even brave enough to tackle the sticky bits of paradox: some of the characters can meet themselves. It has some interesting twists: how much can Cameron be relied on? It's okay with killing sympathetic characters and changing the minds of established ones (in contrast to, say, the X-File's Scully who took far to long to acknowledge that anything strange could be going on). It makes us believe that the Connor family is really on a desperate mission to stop Judgment Day.
Here's hoping that like its mechanical monsters it's harder to kill than most of its ilk.
-- Marco Chacon