Pros
There are many technical opportunities for growth especially if you are bilingual and speak French. There is a genuine lack of experienced resources and many opportunities for employment in many technical fields. If you want to move to other offices globally, you can easily make the connections and potentially move elsewhere (at your own expense).
Cons
Key decision makers and and the management approach is all based on the Montreal head-office perspective. Management in Montreal seems to have little time for trying to understand how the people and teams function in the Toronto area and expect treatment of clients and the way things get done to be the same. The management layer demands you be politically savy and develop tight relationships with the Montreal management.