RTD really likes those long-haired brunettes. In the publicity shots, I kept thinking it was Eve Myles and I think we can agree that Christina is a bigger Mary Sue than Gwen Cooper will ever be.
I loved the complete lack of heavy-handed messages in this episode. Humans are not scum, although Carmen must be lots of fun at cocktail parties. . It was the complete inversion of Midnight, which the Doctor even alluded to. Just a nice, fun, get away from the flying metal sting-rays episode, with bug people and an eccentric UNIT scientist for good measure.
The only evidence of Dr. Mope was the whole "I've lost all of them" which was especially irksome and self-pitying and doesn't take into account that he ditched, or drove them away, especially YOU KNOW WHO.
Still, it's hard not to love an episode with a FLYING BUS!