The Maple Leaf Lounge in Terminal 1 is excellent. Air Canada lets you buy your way in for a reasonable price if your ticket is in one of the higher levels. I don't know about reward tickets. If you have a NEXUS card you can get right through immigration. If you don't then the line is faster than getting one is for the US. The time it takes depends on how long the line is and that depends on what other flights have come in recently. When you return, you preclear for the US and there is usually a separate, shorter line for US passport holders.