A must see site in Montreal. The interior is beautiful, especially the altar piece. This is not a bright church but has a pleasantly etherial feel. The French Gothic revival interior reminded me of religious music of Gounod or Franck. Tour (more of a lecture, really) was informative and thorough.
The wooden scultures of local nuns as well as saints and Biblical personnages have a particularly Canadian feel to them. The stained glass, while not especially old, is lovely with a nice variety of colours.
This is a large church but unlike some basilicas there are not a lot of side chapels, perhaps becuase it has no transept. There seem to be a lot of confessionals where chapels might have been. Maybe there was a lot of sinning to be confessed when it was built!
The back private chapel, rebuilt in 1980 after a fire, is a combination restoration and rebuild using modern architecture. Personally, I did not feel it jibed too well - I think a totally modern re-do would have worked a bit better. But the main church is the highlight in any case.
PS: I think Erin might be incorrect on the number of basilicas in North America. I know of much more than two.