George Brown College taking too much time, 8 to 10 weeks as observed personally. For Centennial College, kindly send them the email otherwise it may also take 6 to 8 weeks. Moreover, I have no idea about Sheridan but Conestoga College responds between 10 to 15 days. Durham & Humber College also replied around 30 days. Finally, choice is yours depending on your course contents which is most important.