well I’d say you’d like it if you buy into the whole T1 and T2 (the series assumes T3 never happened, rightfully so) mythology and if you’re interested in more of the backstories and those characters. It is very TVish but it has nice elements (summer glau’s and lena headey’s being four of those, ahaha) and it is really well made. I have enjoyed it so far… for being what it is, a television-ized version of something that would otherwise be R-rated and ultra-high budget…
Haven’t watched the series, but in T3 it is stated Sarah Connor died in 1997. Perhaps the show takes place before 97. If that’s the only reason why it doesn’t connect with the third film, that is.