I read the review of the other Philip T from Hawaii--and I'd say he was spot on. Well, Hawaii does have one of the most interesting and unique costcos in the world. But this Costco had about 95% of the same stuff as the Costcos back in the USA. There is poutine (which I probably would skip) and some swarovski crystal. One of the more unique items is slightly higher end/middle range shoes in a separate display. Oh, and also, milk in plastic bags (very eco-friendly).
The funniest part is when paying, you cannot use your Costco Visa Card here. They do NOT accept Visa at this Costco. Use a mastercard or canadian plastic (aka: cash!). An Uber from downtown Montreal was about $14.