Location: Right smack in the middle of all the outlets. Bring your patience with you when you go.
Stuff: They have a really good selection of produce, canned/dried goods, cheeses, breads etc. They typically sell larger-sized packages of fruits and veggies but at more affordable prices than the city. That being said, sometimes, some of the produce really doesn't last very long so I have questioned their quality. You can find organic cereal, fresh bagels (I believe they're from St. Viateur), fresh cheddar (white AND orange, and marble too!), chocolate, and tea - it's almost a one-stop shop. If you head to their refrigerated section (they even provide coats so you won't freeze your ass off), you will be in a cheese-lovers' delight - they have a TON of different cheeses that are very reasonaly priced. In general, I've actually found some items that I normally get at my health food store, at Bourassa, for less.
Prices: Very reasonable, and often less expensive than the city.
My suggestion would be to go during the week if you can, or a Friday night, otherwise you will find yourself surrounded by hordes of people and battling it out for a parking space. Despite its size, Bourassa has narrow aisles which makes it a little tedious and sometimes annoying, to navigate especially when it's packed.