YYZ is a clean, modern airport that's fairly easy to navigate around. A huge plus is that they offer FREE WIFI! #winning. There's a long line at customs for both residents and non-residents with enough agents that I can count on one hand... but the line is non-existent if you have Global Entry which is something you should consider if you travel a lot. Additionally, there's an ample amount of outlets throughout the airport which is another great plus. I didn't get to experience the complimentary iPad use because it wasn't offered at my gate, wah!
Cliff Notes: Clean, modern, free WiFi, long customs line, get Global Entry, tons of outlets, and you can order food via iPad at certain gates.