Each of these colleges has its specialty program. So, you should choose one of these three colleges based on the course you are choosing. It will be even better if you reach out to employers in your field, and find out which college they prefer. The Architecture program is widely recognized among recruiters. Most employers prefer technologists from Sheridan. 

Mohawk College is known for its health and technology education. Most recognized programs in George Brown are Culinary Arts, Business, Design, etc.