I really enjoyed this place while in Montreal. I visited once in the beginning and just before leaving, and both times were excellent. I have heard that everyone has a different opinion of the best poutine, but I think that is because there are different aspects of the poutine experience to like.
I would say La Banquise excels in variety. Their menu is extensive - I tried the 3 Amigos and La Kamikaze. Both were awesome. The service was quick and the servers were polite. The location is right by Parc du Fontaine, which is nice to chill at after such a filling meal.