I live in Halifax but have lived and worked in several cities around Canada. If you are not accustomed to Canadian winters, this will be one of the hardest parts to endure. And even if the cold does not bug you so much, the social life all around Canada changes dramatically like the seasons. Winter season a lot of people tend to hibernate, summer everybody comes out. The colder the climate in general the shorter the summer (and connected social life is) Notably in colder areas winter sports tend to also show up but to a somewhat lesser extent. Also a challenge for since I grew up in a sub tropical country. Dont know how to ski, and not particularly good in ice skates and a little old to break bones at this point. This tends to limit you.
For job purposes bigger is usually better. For social life the same rule applies. If you are from a bigger city, chances are the smaller cities will frustrate you somewhat. If you like a simpler life. Smaller cities in Canada are just fantastic for that.
To help you with your decision, if you have any sense of a timeline I would suggest that you already start to look for prospective employers before you land (unless you have loads of money to keep you going or plan to do medial interim jobs).
The people all across the Atlantic provinces are very friendly and I love living in Atlantic canada. Here's the rule. If you want to be a part of the community you live in, it will however fall to you to actively seek those personal connections. Jobs are fairy easy, life is good, safe. People are kind and tolerant. But you have to make an effort to connect either way.
Anyway. Canada is awesome. I love living here. Good luck with your journey.