That was so much better than the pilot episode, and I liked that episode. They really did push to get Sarah fully entrenched in this whole mystery thing this week and man did the plot keep moving and was fast. I almost feel like I need to see the first two episodes again but this episode was really good.
So so far we've seen Sarah, Beth, the Soccer Mom, the Gangsta, and the German, and it seems like this "person" has been planted all around the world using various stereotypes of humanity, or at least that's what I got from the Briefcase scene and the final scene.
I too was wondering how they are able to maintain this storyline. I think each episodes builds on something bigger and it's going to be like an Army of clones or something. I'm almost worried this show might have a Heroes syndrome (And to that extent, Glee Syndrome) which is great first season but how do you maintain this quality while keeping the story interesting. Still, we're only 2 episodes into a 10 episode run. There's plenty more time to see where this goes, and honestly, I think I might look more forward to this show than Doctor Who.