Fairmount (Le Reine Elizabeth) is a busy, older hotel in the center of town. A very good business hotel (with some very bad rooms), but certainly not the best in town.

Ritz-Carlton is one of the worst in the chain: outdated, lots of small rooms, and a lobby that looks like the building used to be a parking garage.

Le St-James is an excellent hotel. The InterContinental shares the block with the St-James and is also a very good hotel.

I've heard good things about some smaller hotels (the Gault, among others) but haven't stayed in them so can't comment.