Scott Aaronson and Giulio Tononi debated IIT five years ago. Personally, I think Aaronson had by far the stronger argument, and my much less analytical response to IIT is that it broadens the definition of consciousness to the point of being uninteresting and unhelpful.
From the article (Christof Koch's words):
"The theory fundamentally says that any physical system that has causal power onto itself is conscious. What do I mean by causal power? The firing of neurons in the brain that causes other neurons to fire a bit later is one example, but you can also think of a network of transistors on a computer chip: its momentary state is influenced by its immediate past state and it will, in turn, influence its future state."
In this view, a building with a thermostat would seem to be conscious to some degree. I very much doubt that any amount of study of simple systems that fit this definition will tell us anything useful about the sort of consciousness that is displayed by, for example, humans.