For me it all depends--somtimes I can tell right away something is not going to get any better and am proven right when I check back with others that stuck with it.I don't know why people bail so easily/early.[ I believe it takes three episodes, at minimum, to establish a series (in fact, some writers often begin the scripting stage with episode three) so I don't agree with giving up on a series after episode two - it's far too early.
Other times if I see a potential diamond in the rough I'll stick with it for 10 episodes to see if it continuously improves before bailing because a lot of serialized shows take that long for the viewer to get a grasp of what the series is really about i.e. CAPRICA and V.
But Persons Unknown is just giving me the distinct vibe I won't miss out by passing on it. It also doesn't help that I'm bored everytime I watch it and the characters aren't interesting.
I agree "The Prisoner" remake was a mess so PU is about on par but LOST was waaaaaaaaaaay more compelling than PU.This is much better than "Lost" or the recent rehash of "The Prisoner" (and also resembles slightly something I wrote back in 2002 - so it must be good, eh?).
LOST did what other high concept serialized dramas these days aren't doing--grab the viewer from the very first episode and keep bringing them back with interesting characters, interesting plotlines, creative out-of-the-box writing and great twists. Shows also need to ratchet it up making every subsequent episode as interesting as the next having you on your edge of the seat for what happens next. I used to love episodic tv but it just doesn't cut it anymore.