Universal healthcare: are there more pros or cons?

So, I live in the US, and we don’t have universal healthcare.

Every time I bring up the idea of universal healthcare (mainly in a casual conversation) I always get the response: “there are too many negatives” “it would never work” “it wouldn’t work here”

I was wondering, if you are in the US, do you think there are more pros than cons/vice versa? What do you think of universal healthcare for the US?

Those of you outside of the US: do you see any downsides to your universal healthcare? Are you glad you have it?