This series has it all, great suspense, nice and smart storylines, interesting characters, suprisingly good cgi for a series,...
Summer Glau is awesome as the friendly Terminator, Thomas Dekker may very well be the John Connor James Cameron had in mind when he was directing his films, but arguably the most interesting character is Garbage's Shirley Manson posing as Catherine Weaver, head of the mysterious Zeira Corp.
One could argue the pace slows down a bit during mid season, but luckily the episodes are never a bore. On the contrary. From all the slower episodes I particularly enjoyed "Self Made Man".
The strongest part of the series, though, is continuing the events that followed on T2: Judgement Day and ignoring T3: Rise of the machines and Terminator salvation, thus creating a new timeline. The storyline is much smarter than that of the last films. Especially the season's finale (sadly also the end of the series... Damn you FOX) will keep you wondering for a long time. At the best of it all is that the more you wonder, the more it all makes sense.
Don't hesitate and buy your copy. Terminator and sci-fi fans will not be disappointed and maybe FOX will realize one day what kind of potential it had in its hands.