I've never seen canned cod liver where I live, but I would eat it if I had access. I would include it in my mix of fish I already eat, certainly not just canned cod liver. Maybe 1 or 2 servings a week or month surely would be fine.
I try to eat fish every day, mostly canned sardines or oysters, but also fresh fish when available. If I get stuck eating out, I will always order the fish over all else.