Hi sszeto,
Before you consider a major brand mattress I would make sure you read post #1 here which has all the basic information, steps, and guidelines that can help you make the best possible decision.
Some of the better options I’m aware of in the Toronto area are listed in post #1 here. There are also links to some of the forum thread from other members in the Toronto area in post #2 here which may also be helpful.
Phoenix