Free wifi!
So Terminal 3 kind of sucks, at least the baggage claim area, but the rest of the airport (Air Canada terminal) is super nice.
The airport is clean, well-kept, and mostly modern.
As an American, I found the customs process to not be ridiculous and I'm glad they have those machines that read your card and passport.
I also took the Union Pearson Express, which was brand spanking new, reasonably priced (versus a cab), took only 25 minutes, and was on time!
Prearranged ground transportation process was smooth and the service was great.
I'd much rather fly into YYZ that YTZ any day.