I've been to the Bell Centre five times in my life for Canadians games. All five times I left in awe!!! The place is HUGE with a 21,000 capacity for sporting events, and I'd guess an additional 3,000 for concerts.
The air inside for hockey is electric! Location is prime too. You can get to high quality hotels, Casino de Montreal, delicious restaurants, fun pubs, and great shops all within walking distance or a short taxi ride. The concessions and bathrooms are well placed and reasonably priced (for being an arena).
The only negative I have is that for 21,000 seats the concourses are so narrow! It will take a good amount of time to get out if you stay till the end.
This place is a must see if you ever get the chance to take in a game or concert in Montreal!!!