Pros
The best part of working here is the people: everyone is excited to build good code and solve the problems that are put in front of us every day. I was stagnant in my previous job, and have grown enormously since joining Shopify 4 years ago - both in my programming/craft skills and then also as a manager, a position I decided to try out for the first time (b/c the people around me making "management" appealing - they require very little management).
Cons
The ground can shift relatively quickly here. The company itself is a stable, but the problems we're trying to solve can arise quickly - like the weather. "Thriving on change" is considered healthy here - but if you're looking for "years of stability doing the same job over and over", that may be a challenge for you. But if you like responding to challenges, it's a good thing.