I think it is a bit late to provide you with a reply, but I would be happy if you could let me know which offer you finally ended up with.
I just finished my master's degree at the University of Waterloo and got accepted for a Ph.D. program at the Ohio State University. To briefly give the readers an overview of my experience at UW, it is one of the best engineering schools in Canada, especially in Computer Science, with outstanding faculty members. However, the funding for master students is not as generous as the one provided for Ph.D. students. The reason that I am leaving Waterloo is that I am specializing in a field which is not that active in Canada. Thus, the U.S. and especially OSU is a great option for the topic I would like to be working on.
All the best