If you are flying into Montreal from another country this is the best way there.
The good. There are many snack shops, stores, places to eat and free wifi. The TSA, security and border patrol coming in and going back out are well labeled and fairly efficient.
The bad. If you are traveling Internationally, plan on a 1 mile walk by the time you get from the terminal to customs, bag claim and then out to the transport areas. At least it is nice, clean and well labeled.
Enjoy!