I attended a conference here in 2006, and it was a great convention center. It was spacious, the rooms were comfortable, and facilities were spotless. Another plus is drinking water was provided throughout the conference in the rooms - this seems so minor, but it really is a major plus in heavily air-conditioned (dry) conference centers. Bonus, there is a Tim Hortons in the place. And a few other spots to eat as well, so you don't need to leave (or can find something if you cannot leave the premises).
It is centrally located, so there are a number of hotels that are close by or even connected to the convention center. In addition, the "old" section of Montreal is within walking distance and there are some great places to eat in that area too.
And oh yeah, this convention center was used for some scenes in the movie "blades of glory", which was a really funny movie.