This was the best episode this season, by far. And yes, I realize that isn't saying much.
I agree with what others have been saying as far as Astra's redundancy, but she hasn't been around a lot (yet) so I'm ok with her making occasional appearances as John's protege. Ryan and Swann are both good actors, so at least there's that.
However Spooner? Just... why? I hope as soon as they find Sara they write her off, because "alien detector" is a very limited ability - plus she's pretty unlikable in general.