Montreal, quite simply is a sh!t hole, especially when compared to other North American cities of similar size.
Taxes are outrageous, people are ignorant (as the example from Liberalman points out), the weather is awful (it rains for 7 months a year, snows for the other 5 , the summers are unbearably humid), freeways are crumbling, public transit is not air conditioned, product selection is limited (if it's not in French, it aint here) the list goes on ...
I spend more money driving to Ontario, New York state or Vermont every weekend to buy things that have been banned in "la belle province" than Montreal's low cost of living will ever save me. "Joie de vivre" is apparently a trip to Plattsburgh to buy cheese that wasn't **** out of a goat last Wednesday. They don't mention this in the brochures.
The Quebecois (English- and French-speakers alike) have no clue how the outside world works. Indifferent service in restaurants, terrible pizza (plastic cheese, wagon-wheel pepperoni placed under said cheese with no sauce) and "expresso" are a way of life and everyone tells you "c'est normale". It is a very frustrating place for anyone who is used to the rest of the world. It's fun to think of all this as distinct society or a novelty for a while, but it gets tired after the first few months. It doesn't take long before you that this place seriously screwed up.
The one upside might be that because so few people want to live here, real estate is actually quite affordable. Your money, however, could get a better rate of return elsewhere.
I notice from the date of your post, you've probably either decided to stay put or accept the position with IATA in Montreal. Whatever your decision, I hope it has worked out for you. Some might notice that IATA is a quasi-governmental organization (UN). Most free enterprise has move elsewhere in Canada. Most of what remains in Quebec are government bodies (VIA Rail) or Quebecois banks such as National and Desjardins. This is certainly a place on the decline.
For anyone else considering a move to Montreal: stay away, stay far away.