The writing system is easier to learn. But the pronunciation is a lot harder to learn than Japanese, and the grammar harder to learn than Mandarin.
There's also the fact that Mandarin has a lot of non-native speakers who are Chinese. I believe 400 million in the PRC, or 1/3rd of the population, only have a basic grasp of the language. Even a lot of the fluent speakers have thick accents. So the Chinese are used to speaking in Mandarin with non-native speakers, something that the Japanese and Koreans aren't as accustomed to.
I agree 100%. This is, I think, and underappreciated aspect of language study. Chinese people speak Mandarin with accents, so they're not irritated to hear my accent.
There's also the fact that Mandarin has a lot of non-native speakers who are Chinese. I believe 400 million in the PRC, or 1/3rd of the population, only have a basic grasp of the language. Even a lot of the fluent speakers have thick accents. So the Chinese are used to speaking in Mandarin with non-native speakers, something that the Japanese and Koreans aren't as accustomed to.