Vantaggi
The people: Stantec does their very best to keep good people and to promote a healthy and happy work environment. They also have a great working model of "local" offices to serve loval clients. Those offices are often full of people who work together and are also good friends. Coming to work with people you like makes any job way moe awesome! Also - refer to my comments on cons below where I mention the public company aspect. One other major benefit to working here is that anyone can wmove up and be someone important at the firm. That's because you don't have to "buy in" for part ownership like in a partnership agreement. You can just be good at your job and move up and be recognized.
Svantaggi
It's a public company so the needs of the shareholders really matter. That said, in a privaet company the bank accounts of the partners also matter so maybe it isn't a "con". At least a public company is fair and regulated and you know for sure that the leadership team (which is awesome, by the way) is following a defined set of rules.