As an international airport, YYZ suffices. Terminal 1 is modern and fairly sleek, although Terminal 3 is getting a bit dated. The recent efforts to improve the post-security food offerings are much-appreciated as well.
The good:
- Free and fairly consistent Wi-fi
- US customs preclearance
- Organized by airline alliance (*A is T1, OW and Skyteam at T3)
- NEXUS and Global Entry kiosks (but some of the Nexus machines seem to always be out of order)
- Decent food/beverage selection as well as lounge options
- Priority security lanes
- Clean facilities
The bad:
- Horrendously slow baggage claim service
- Long walks to/from gates
- express moving walkways are always broken
- New iPad bars near gates reduce available seating
- Terminal 3 starting to feel old and dated
Although not as nice or well-furnished as some other global hubs, YYZ manages to hold its own and for a North American airport it's definitely quite decent.
I wish they'd rename T3 to T2 or something though since it just feels kind of weird to be missing a terminal.