Le Vieux Velo, in Little Italy, is one of my favourite brunch spots in Montreal (and that says a lot, as there are sooo many amazing places). The decor is simple and their menu is small but they do their items just right.
Their eggs benedicts are delicious - and they have pesto hollandais sauce which is a lot tastier and less heavy than usual hollandais sauce in my opinion. I've tried both the BAB (Bacon, Avocado, and Brie) and their Veggie Pesto Benedicts. Their benedicts are priced at ~ 9$-11$ which is probably the best you'll find in Montreal.
This place does get pretty busy on the weekends but their service is fast and I've never had to wait more than ~20 minutes. Next door is Cafe Odessa so I usually just hop over there for coffee while I wait. Vieux Velo serves brunch all day so you can go later to avoid the rush.