Back in the 1980's, walking out of Terminator utterly dumbfounded, I'd have killed for this show. It may lack some elements of perfection (the prison-break in broad-daylight where the main characters deploy their terminator with lots of witnesses leaves something to be desired) but it's most a tight show with strong actors, a load of charisma, and relentless pacing.
The high school elements are some of the most intriguing with Glau's awesome grief counseling scene and some of the other interplay (it'll be interesting to see what happens if someone picks on John or Cameron, both of whom could pretty much take the school apart with their bare hands). The evil terminators continue to be fairly threatening and plenty persistent (although, again, the terminator loose in jail would, I think, raise a lot of questions beyond just the prison break).
Clearly there is a solid back-story here too: the plots are pretty tight but they tie together well and play attention to the Terminator canon. I think the authors did their homework and did pretty much what I'd ask for in terms of keeping the show from being either pure formula (with each episode utterly disconnected from the others) or simply having a shallow understanding of the material and just playing it up (the way T3 did).
So far it lacks the utter jaw-dropping spectacle that BSG had or that Firefly presented. The show is excellent, not transcendent. But give it time. It seems fairly brave (the suicide scene), willing to take some time (the John-dad plot-line), and it understands that it needs to give us both normal-life-as-time-traveling-fugitives and action-movie fireworks.
Back then I'd have been nuts for something like this and today, even with all the intervening years, I'm glad they're doing it.
-- Marco Chacon