"The best laid plans of mice and men ... " -- John Steinbeck
On countless trips to Montreal and otherwise, I have found that the Internet cannot predict the entirety of your trip. Not every tidbit of information, especially local info, is online. Montreal is definitely a city to be experienced in person.
Especially with Montreal, there are usually pleasant surprises. A delightful little cafe tucked away in a corner of the city, or in an underground metro station. An impromptu museum made out of a historical home. A fascinating painting or sculpture placed in the lobby of a shopping center. And none of these are likely to be documented on any website or message forum.
You can only plan so much, but the improvisational nature of time in Montreal is often an attraction that alone is worth the trip.