This is a pure perception problem, when you talk about Luisiana State University, everybody in US knows what LSU is all about, its football team, and so on, although its computer science sucks. The problem in US is even professionals (such as graduate recuiters in graduate schools) only know how their programs rank among US schools only, unless there is some reason for them to know a foreign school is good( for example, mcgil's free softwares). I know waterloo has a better CS program than Mcgil, but if you want to apply for graduate scholarship in a good US school, the decision usually depends on how much the graduate director has heard about the school you come from.