And while we're on the subject, the 456 are brilliant. None of this sticking a cats head on someone and playing it for laughs. No sir. These aliens have balls. Balls that presumably require that poisonous alien atmosphere in order to fire out that pea-green extra-terrestrial death-jizz (I really wish I hadn't had to type that), but balls nonetheless. It's hard to tell within their atmospheric box, but if anything they look like the bastard offspring of a Yithian and that giant mantis that tried to eat Xander. They're awesome, and they want our children. Frankly, you could have removed Torchwood entirely from this story, just hung it on the international politics/human cost angle, and it would probably made the whole thing better (and shorter).
Which is kind of the problem, really. As has been mentioned, Torchwood as a team are at their least irritating ever, but Barrowman and David-Lloyd are still fairly weak actors, and Gwen and Rhys still annoying far more often than they're anything else (the "Jack found out first" subplot is particularly retarded; he walked in on the fucking scan, that's all you need to say, you daft woman). The international fall-out of alien contact (done properly, this time) and a world full of crazy mind-controlled children is way more interesting than whether Ianto wants to be in a relationship.
Mind you, even I'm interested in Jack's role in the original 456 encounter, so for now I'll let it slide. Really, though, you can't help feeling this could have been done entirely separately from the Whoniverse and it wouldn't have hurt, and helped in several areas.