Mississauga Rocks! I have flown Air Canada predominately when I fly to Toronto. Terminal 1 is Air Canada town. Modern design. Smooth self check in.
The customs procedure is always painful and the line is long. I am just trying to get home. I noticed the difference between pre 9/11 Canadian Customs and after 9/11.
Clear signage to locate luggage and get to taxis and airport shuttles.
As long as I stick with Air Canada I should have no problems with this airport.