Massey Hall is a concert venue with full seating. It's the smaller end of the stadium seating venues which includes places like The Sony Centre or Roy Thompson Hall. The sound system is excellent and the seating comfortable. Even sitting on one of the upper levels, I had no problem seeing the stage, hearing the music or enjoying the show. Well, so long as you don't have a giant column in the way...
If you plan on going out for dinner before the show, make sure you give yourself plenty of time, because the nearby places like Fran's usually fill up very quickly.