This is easily the largest outdoor beer garden in downtown Montreal. Their back patio in the summer time is crucial and usually filled with good folks enjoying cheap pitchers among archways, stone fountains and ivy covered walls. The inside area is just as vast with four floors of pure awesomeness and balconies on each level. Different music marks each level and the outside stairwell is not for those scared of heights. When I was in University at McGill, St. Sulpice was always an obvious destination yet it manages to attract such a diverse crowd that it doesn't feel fratastic and douchey.
It's basically every great bar you've known, thrown together to make a single awesome venue. If you visit Montreal, this should be on your list. If you live in Montreal, well then I'm just jealous.