I've not had any problems at all carrying laptops (yes, I carry two) in and out of China. In each visit, nobody has even bothered to look at them besides running them through the standard X-ray machines.

I have, however had a bad experience with Israel. One of the laptops did not pass a chemical swipe as I prepare to leave Tel Aviv. Now, this laptop has so far passed tests at LAX, CDG, and FRA on the same trip. TEL security took just about everything apart, but was still not satisfied. They kept the laptop and asked me to pack all accessories in checked luggage. The laptop arrived at my home 3 days later in a cardboard box without any packaging materials. It no longer works, and neither the airport nor airline will reimburse me for it.