A multi-story parking garage with a distant view of all movements on runway 17L and the north side of the new terminal. Rotations from 35R departures are visible too. Towards the southern end of the facility, you can see taxiway Romeo in the distance in addition to the Air Canada hangar and some of taxiway Juliet.
The location offers a nice view of the runway, along with the northern part of the new terminal that's currently under construction.
It may be high up, but it's very far from the runway. Rotations from 17L takeoffs will be blocked by the new terminal.
I have not had any issues with security from this location.
You'll need a LOT of zoom to get anything from this location. Allow a couple minutes to drive up to the top level. When driving in to the entrance off of Airport Road, head to the "Through Traffic" lane, and keep driving until you reach the P2 long term entrance. Best place to stand is near Stair #4. Parking starts at $10.00CAD and increases by another $10 each hour.
Videos from this location:
https://www.youtube.com/watch?v=klpxobTcj90 (National Air Cargo 747-400BCF landing on 17L and taxiing on Romeo)
https://www.youtube.com/watch?v=6MM6XhBt0YA (Ilyushin Il-76 landing on 17L and taxiing on Romeo)
https://www.youtube.com/watch?v=ydGhqtg0EzA (Air Canada 787-8 landing on 17L and parked at the gate)
Pictures from this location: