If you don't know French some opportunities are not at your reach
There aren't a lot of positions, depending on the area, also the market seem to put outsiders in 2nd place (basically anyone that's not from Quebec)
Most companies I've worked with in Montreal, english is often the main language in the office (almost to a fault) and companies are STARVED for talent. It's very, very hard to hire people in Montreal, there's a lot of competition (like pretty much anywhere else). Outsiders are very welcomed if they bring well needed help.
However, salaries are very low, taxes incredibly high and while real estate is affordable, don't expect to live close to the city or to have a lot of money in your pocket at the end of the day.
Most tech people working in the US likely will be shocked at how little tech workers are paid in most of the rest of the world, including Canada. But not everything is about absolute salary.
Montreal, imo, provides a well-balanced quality of life for a wide range of demographics. Good schools and govt-provided health care for those with families. Bilingualism for the culturally inclined. Nearby mountains and wilderness for nature lovers. Unrivalled nightlife for the younger who want to party it up. I don't know of another place that can offer all of those things together.
I mean don't get me wrong, Montreal is a nice city to live, the culture is great, the people are nice, a lot of great restaurants and what not. While I don't think healthcare is that great, if you don't have insurance, it is enticing to think about.
However, from somebody coming out of SF, they do have to expect their in pocket income after expenses to drop significantly, on the range of 50 to 60% and up. In this case, salary is a VERY important consideration.
To put this in perspective though, you can rent a reasonable 2BR for 800-1000, even not that far from the city center. GF and I rent a 1BR a bit farther, but still close enough that she can bike to her downtown work in the summer, for a fair amount less than that.
"and companies are STARVED for talent. It's very, very hard to hire people in Montreal"
Yadda, yadda, yadda
I spent a couple of months sending CVs around Montreal (this was after having Canadian experience) to no avail, just to have several ones take me seriously in Toronto and actually make an offer
So yeah, they're starved by their own doing.
(And I do speak French actually)
The city is lovely, very cultural, I love it, but the fact that it's an Island makes real-estate issues "interesting". Worse taxi-drivers on the planet though (but now there's Uber)