The obvious question is "how do they manipulate anything?" (a related question is "how do they put their trousers on?!"
). Their claws are huge and very unsuitable for fine manipulation - not exactly good for a technological species.
This sort of comment is essentially parallel to my complaints about too many alien races that Look Cool until you try to make them make sense in their current environment. The questions that too many Cool Alien designers forget to ask include things like "Why did they evolve this way in the first place?" "What were the evolutionary pressures to develop sapience?" "How do they control and manipulate their environment?" "How did they become a tool-using species?" Quite often, those answers aren't forthcoming, and the species in question seems to simply be a human in a funny suit - which, when he's offstage, he takes off so that he can actually DO something other than Look Cool.
I believe that form follows function, and that the function is largely determined by the environment/niche being filled. For a human-grade species, there's still plenty of flexibility, but I suspect that an endoskeletal bipedal/upright species with fine manipulators and clustered sensory organs is going to be part of a common baseline.
I have trouble with the idea of a species' locomotive appendages also being their manipulatory appendages, and additional trouble with the idea of a sapient species that is essentially parasitic on another.