My 2 favourite QC restaurants are Panache and laurie-raphaël. Both are somewhat expensive fine dining places.

Panache happens to be in my favourite QC hotel, Auberge Saint-Antoine, which is a Relais & Châteaux hotel. Le Chateau Frontenac is a very imposing edifice, but I found it unimpressive as a hotel. OTOH, it is a classic, and may be worth considering if QC is a place you're only likely to visit once. I'm not familiar with the Courtyard by Marriott there.