Slightly better than its predecessor, but only in that there is a bit more action to move things along. All in all, a lot of the same issues from the previous book stand. Characters are largely hollow and their motives change to suit the plot without enough explanation as to why they would suddenly change their motives. They also tend to appear and disappear in the plot without a lot of preamble or explanation. There are a lot of sudden changes or addendums to the "rules" of the aliens' technology, as if the writer kept writing himself into a corner and had to explain his way out of it. Getting stuck in your writing is fine, but you should weave changes to the rules back through the rest of the book so that the reader isn't suddenly blindsided by all these additions.
In summary: good ideas poorly executed.