What is the routing?
Polaris awards a not super easy to come by which sucks.
If you are based in Europe and just want to get there quickly, I'd probably go with AC if the times aren't bad.
From Europe to the US via Turkey would just be too much of a detour for me.
Air Canada has the Signature Suite, which (when open) is at least somewhat comparable to the Polaris Lounges but cannot be access on an award ticket.