How are you going to leave your job in NYC and take one in Montreal? That would be near impossible to do it the other way around so I am thinking it would be difficult to go from a job in NYC to a job in Montreal unless you are an expat or something. I don't know for sure but I know Canadians trying to get green cards has been difficult. You have to make a case that a particular skill is underrepresented in your country.
Its "Relatively simple" when / if you get a job offer and letter of employment from a company, and if you are degreed, experienced professional, all you
need is a work permit / visa under NAFTA** agreement which is good for one year (renewable) and it would cost about $50.00 US (As of couple of years ago).
Note that this is different then the H1B visas.
I did the opposite going from Montreal to the US and worked at some of the top aerospace companies by just this work permit / visa for about 10 years
without trying to obtain green card status...
As everything else, moving to Montreal, there are pros and cons, although, pros being the price and the availability of the girls (Especially with the agencies)
but you will be be paying 100% of the cost, but when you coming from the US you have a discount on almost everything, and while traveling outside Canada
everything will cost you more (Whatever the exchange rate is). Also as a non Canadian citizen, most probably you will have to pay for medical insurance
and that would cost some extra $$s. (As I was paying my own insurance while I was going to the US).
One thing I like to add that, these days is little difficult to go to the US (Things changed after 9/11, America first, Trump policies*).
*But one thing I would agree that Mr Trump wants to modify the system and make it easier for professionals unlike the present system that mostly
is based on family connections and sponsorship (Green card via employment is possible but it takes long long time).
** Is about to be replaced by the new USCMA (Or whatever is called) deal if it goes through.