I've eaten Chinese food in Japan, Thailand, India, Australia, Italy, Spain, France, Belgium, the UK and the US, and all were completely different.
India's is somewhere between horrible and tasteless (anyway they only know 3 dishes : chow mein, chop suey and gyoza).
In Italy and Spain, the menu was the same in every city, with always the cashew nut, black bean, sweet and sour, and oyster sauce for either chicken, pork or beef with a choice of white or fried rice.
In Japan, there are always subuta, ebi chilli, chukadon and gyoza.
In France, it's often mixed with Vietnamese food (there are lots of Vietnamese or Laotians and they have Vietnamo-Chinese restaurants).
That's actually in Belgium, then Australia that I've eaten the best and more varied Chinese food. I still have to try the real thing in China. But there are so many kinds of cuisine in every region that it's really hard to even tell what is real Chinese food like.
Should we include imported dishes like ramen, kare-, tempura, pasta and tonkatsu into Japanese food ?
Anyway, I like both.