Are there any statistical studies about how users feel about this component? is it easy to use? or is it complected for the average user?
This is widely used feature and recently I've taken feedback from my beta users and they are quite comfortable with it, but at the same time it also depends on the feature for which it is being used.
Like for an example in your case it is country selection and everyone might not remember all country name or during typing they might forget it, it is better if you give multiselect list with checkbox. along with search box where one can also search and then check it out.