Good BUT ... good is abundant in Montreal. Garde-Manger is not consistently among top recommendations in Montreal but it makes the list often enough to form some expectations. My expectations exceeded Garde-Manger's delivery in terms of both food and overall experience.
This is another of what I call the "Chalkboard Bistros", fine dining establishments that provide the menu via a large chalkboard on the wall in the center of the restaurant. I don't like this practice but it's popular (for now anyway). I found the menu, limited and lacking distinction / personality, with the same style of offerings that are standards around Montreal. That being said, the food was good, it just didn't deliver on the level that I would have expected given the buzz about the place.
TIP; request the front bar if bar is given as an option. The back bar can become almost another kitchen-like operation preparing oysters and volume drinks. Back bar can also be pretty tight.
TIP: avoid being seated during one of the eating sessions times 6:30 / 9:00pm, the wait-staff can get slammed during these seating sessions and your service delayed and/or intermittent.