I would have liked it more, but I thought the characters were weakly defined and the reasoning made little sense. So the enemy assimilates other being into themselves, but they make some people sick, or were people killing them? There was the theory that the enemy could just go straight to earth, but chose not to in order to ensure that all people are assimilated? Maybe the idea that they are collecting some people to understand the human strategy makes sense, but collecting all of the species would seem a lot easier if they went straight to the homeworld, leaving the rest stranded, to be picked off at will.
Then there is the boyfriend who is practically a throw away. The protagonist is leaving to protect him at the end, but sure has no qualms leaving, no doubts. I also wonder about marrying a group of clones. If they are people, and anything like twins, they would want to be individuals, not part of a group. I know, because my mother is a twin, and they have their own lives and interests. I don't think one would feel too special to be married along with a group of your clones. These quirks make them seem less than human too me and hard to relate to.
It is an interesting future world and one that really has potential. Ideas such as creating clones to fight wars, but having an enemy that can turn them against you, and get your secrets to boot. The ideas of personal identity and relationships. I just had a hard time investing in the characters this time.