No system is perfect, but I know a lot of vets that get really good healthcare through the VA.
All healthcare is rationed. Right now we ration on the basis of price, ability to pay, and ability to secure insurance. Single payer systems use a different set of criteria for rationing, things like: age, survival rate for given treatment, quality of life, etc.
As the US blunders around for the next 20 years, I expect medical tourism to explode both in country and out of country.
Example: a friend just priced out a yet another heart stent for her husband. $90K at a famous hospital in Chicago, where they had been referred, $45K at a local hospital 30 miles out of the city. Surgeon fees extra.
The Amish, who do not believe in insurance, travel to Mexico for surgery for things like cancer. I've heard of people traveling to India for hip replacements. Someday somebody will put together something like Travelocity with ratings for medical tourism and it will explode.