Not the worst airport in North America.
The biggest detraction about Pearson is something it can't change, it's huge. And your departure gate will always be as far away from security as possible.
That being said, some of the quickest security lines for such a large place. Also, well cleaned.
I travelled both to and from using the TTC and did so from Parkdale in under an hour each way. Not bad for the fare price ($3 at time of travel). Not as smooth as Vancouver's Canada Line (20-30 mins) but not bad.