This is a somewhat controversial topic.
There are those who argue that the effects of imperialism are all negative. These people argue for ideas such as dependency theory. This idea holds that the problems experienced today in places like Africa and Latin America are due to imperialism. Such people argue that imperialism ruined the countries it touched by orienting their economies to the needs of the imperial powers and by denying them self-government.
Others, however, argue a more nuanced view. These people (Niall Ferguson is perhaps the biggest name among these) argue that imperial powers actually helped their colonies to some degree. They claim, for example, that European countries brought modern medicine to countries that would not otherwise have had it. They often make the same claim about Western education and democracy. They argue, overall, that countries are farther ahead today than they would have been without imperialism.
In these ways, there are different views about the effects of imperialism on our world today.
You could read a book, Homeland by George Obama, who grew up in Kenya, a former British colony. Some of the reviews suggest that he compares life in Kenya with life in Malaysia, another former British colony.