I can't help but feel that many of the reviews here are slightly prejudiced, in no disrespect btw. I completely get the argument that it's slow - yes, I agree. Sometimes, at points and at times it's lethargic. The characters (some of them) are weak, and the attempts to make the audience reconcile and actually like some of them are often futile. But I also feel like some characters have been worked excellently.
Yes, there are multiple random story arcs with limited resonance but that's a refreshing take on TV. Yes, there's very little "Invasion" happening for a series named "Invasion", but overall I feel like so far it's building its way up. Little by little we are introduced more backstory, which allows for such powerful scenes (the ending in this episode and some other scenes in previous episodes).
It's slow, but for a reason.