I would say not equating Chinese and US surveillance is rather dangerous. Not the extent but the capability and willingness (and track record?), clearly exhibited by instances that they can and they will. They both surveil their own citizens and of course citizens of other country's. Or maybe because USA is better at it? Doing it and getting away with it most of the time?
Besides "largely" the keyword here as an artificial differentiation only leads to some kind of general denial (by its own citizens) that works in the favour of USA's surveillance machinery.
My issue with this is that, in the US, PRISM was shut down--whereas in China that would never happen. The US by no means has a perfect or even necessarily good track record, but the people in charge are still accountable to the public and that makes a world of difference.
Besides "largely" the keyword here as an artificial differentiation only leads to some kind of general denial (by its own citizens) that works in the favour of USA's surveillance machinery.