I'd say both real and hyped. No doubt there's a threat and an issue, but I also have little doubt that the threat has been oversensationalised. It's also fairly obvious that the same things are being done in the opposite direction, along with various other countermeasures (such as setting up defective or erroneous data for theft). The Chinese are neither omniscient not omnipotent, and the people on the other side are not entirely inept.

Given that as a general rule the most effective intel operations are the ones that remain unknown, it's very difficult to say what's bigger, better, most extensive or most effective.