If you really want to be in US, than you should go for US than.
But you are already have
PR in Canada you are treated here as a person who has all the rights , well, except for the right to vote
On the other hand you are trying to get in US. For that you are trying to get a working visa than you are going to try to win a green cart. When that going to happen - who knows.
So as total: Canada - you have a stable position - with free medicine as a bonus. US - unstable position. You choose.
In my language there is a saying: "Better to have a small bird in hands than a big bird in the sky" Not trying to offend, but for me it's really describing a position you are in.
From our experience, well when we were waiting for the news from a Canadian embassy about our immigration process, my husband get a job offer from US(with a H1 visa). We choose not to go in US.
Good luck in any case