Depends on what you have going on with the DVR. I have not noticed the Slaves (C31/700) units to be slow to do stuff. I did get rid of the MoCa, and plug my ethernet, directly into the back of my HR-44/700, which did make a big difference.
It would have been nice if Pace had made the C31's, capable of using Ethernet vs. Coax for the network between the boxes. That way if you did not have Coax in a room, you could just connect them to the DVR with Ethernet.