The burgers are incredibly juicy and flavorful. Pricing is very good given this is a service joint (you're served at the table). Everything is home made and is fresh. Fries are awesome also and so is the poutine. Menu is simple and service is fast and friendly. I really highly highly recommend this place.
For comparison purposes, I've had burgers in A LOT of places, including some higher end burgers in restaurants like Chez Victoire (their rib burger is amazing also) or fast food joints in the us like in-n-out or steak'n'shake taht are known for good tasting burgers.
Hands down best burger in Montreal is at Queue De cheval (QDC Burger). During winter they only serve them inside the restaurant for lunch only, but starting April 13th, they will start serving them outside again in the back alley of the restaurant and it will be open all day until 3-4am.
They use trimmings from their premium aged beef for burgers. It's just unreal and no the price is not super expensive, it's about 15$ if I remember right