Chinese has so many distinct regional varieties that I don't consider it fair to compare the whole of Chinese food to the food of the Japanese island. For example, most Westerner exposure to Chinese food is limited to Cantonese with a small addition of some Sichuan dishes. There are a number of other regions and methods that people are almost completely unaware of. With that said, I still couldn't pick. Chinese (all of the variants), Japanese (and its variants), Korean, Vietnamese, Thai, and so on... all are so good and have such distinct and subtle variance, that I find myself always looking forward to trying anything/something new and previously unknown to me.