We stayed three nights at Hotel St-Denis. We were in Montreal for a visit and wanted 1) an affordable ($100CA or less/night) place to hang our hats, 2) a hotel close to the Metro system, 3) somewhere with an option to store the rental car for the time we were in town, and 4) somewhere clean but not requiring any frills.
Hotel St-Denis fulfilled all these requirements admirably. The rooms were simple and very nicely kept up, beds were comfortable, plumbing worked, and the price was right. The room was quiet, with no discernable noise through the walls.
As far as convenience, this place is a block from the Metro hub (Berri-UQAM), giving us easy access to any neighborhoods we chose. This was by far the most beneficial aspect of the hotel. Anyone wanting to use the public transit system in Montreal is advised to be near here.
Car parking was half a block away for $16/night. I have paid or seen substantially higher prices in other major cities.
My overall impression is that this hotel is fairly priced for what we got, and I would certainly consider staying here again. The proximity to transit is certainly the best aspect of the place.