I'm French, but imo it's China by very far ... which is not even in the poll although being widely reputed
My wife is Chinese then I can go to eat in various places there, not only tourist-specialized places, and Chinese food is extraordinary in my eyes.
Especially the variety is much higher than for French food (which I love : I'm French and always try to eat in restaurants with 3 stars in the Michelin guide
) and all other countries I know. Except that a huge miss is desserts and wine of course (and cheese) but still, the variety is overall much higher in China than in France.
Vietnamese food is also great, but the difference is that it would be one of the best regions for Chinese food if Vietnam was part of China (I spent a very short time in Thailand but I had the impression that the food there was also great),
but China has so many regions with different kinds of food, and in big cities you have restaurants from all regions of China, which makes that you can enjoy such a variety
And also in China, you don't need to go to very expensive restaurants to enjoy great food, in France the basic food is not that great although my mother is a very good cooker and creates many dishes herself
I think it's hard to judge if one hasn't been to China, because unfortunately it's hard to find restaurants of such quality for Chinese food in France. Maybe in countries with a larger Chinese community it's easier.
Anyway, from what I heard, China and France are well-known for how important cooking is in their culture, and I think it's true : in both countries people love to talk about food
And I think that the culture of cooking is usually small in the western world comparing to Asia, hence I think that people who mostly speak of western food really miss something.