Sheraton Montreal is notorious for not providing SPG benefits. Too bad the Westin in no longer operating in Montreal. As for the Sheraton in Toronto, it is one of the best located hotels in the city for getting to various sites without having to rely on cars, taxis or even public transit. One can walk to just about every major city centre venue, and even down to the lakeshore to catch a ferry to the Island. And if it is too hot, it is linked by underground pedways to most of the major shopping malls and office towers. Or to the subway if you feel a walk up to Bloor Street is a bit too far in the heat.
If you clarify a few of your personal interests, I will be pleased to post a few suggestions about places and events you should try to get to while here. Will you be here with childen? Do museums and art galleries interest you? Do you like drinking craft beers? Have you considered a drive out to Niagara Falls for a day?