So my first reaction on finishing Slow River: "What? That's it?!?"
There were a few things that prompted that reaction. First, I didn't feel like Griffith really pulled off the conspiracy with Greta very well. There was only the mention that she "had to have secret power" there at the end, and that she had been perverted by Katerine to explain any of her conniving and plotting. The secret conspirator at the plant was not very interesting, basically since we never really met him or knew anything about him.
Second, I felt like Lore returned to the arms of her father far too readily, with nothing but a few scolding "Oh Papa"'s to let us know she's angry. There should be a lot more that she has to deal with before she can resolve such deep issues.
Finally, I thought the union between Lore and Magyar, while kind of inevitable, didn't have any real charm.
All that being said, I did enjoy the book quite a bit. The world that Griffith creates, in which companies compete for huge governmental contracts to clean up our mess, seems to be plausible to me. At least, I can't imagine a more likely scenario in which the human race will clean up the earth. There will be corruption and greed in any such large undertaking, no matter how noble the overall motives.
Also, I liked the intricacy of the three plots that Griffith wove around each other, and the depth with which she constructed Lore and Spanner, especially.
It was interesting to note that the only heterosexual couple mentioned in the novel (as far as I could tell) were Oster and Katerine, who were pretty much as screwed-up as they could be. That's not to say that Spanner and Lore's relationship was any good, but I thought it was interesting that heterosexual relationships made such a small appearance.