WebMd's professional-level Medscape site published a pair of articles last week — Single-Payer System: Why It Would Save US Healthcare and Single-Payer System: Why It Would Ruin US Healthcare — that are interesting (perhaps especially in the reader comments posted at each) for how professionals in the healthcare and medical industries see the question.
In the articles and comments, the Canadian system and some others in the world are referred to or mentioned, also Medicare, the Veterans' Administration, Vermont's re-evaluation, Physicians for a National Health Program (PNHP), the ACA and so on, although, oddly, no mention that I found of the Hawaiian system.
Use of Medscape is free, you just have to register. I've been reading there for many years now, initially as a professional research librarian, and have found it a very useful resource personally as well. Here's my usual intro and 'disclaimer' links:
BTW,
Medscape's searchability recently seems to have been "improved" to the point of becoming somewhat the little engine that can't (in German that would be considered
schlimmbesserung) but I'm hoping for repair, as it was remarkably good before.