Agreed, the US doesn't rank first in virtually any metric that citizens would consider to be desirable (like healthcare, education, safety, freedom of the press etc). And it's no more democratic than say most European states.
Taking into context its size is a whole different matter, though. It's relatively easier to build an awesome small country (say the Netherlands where I'm writing from) than a massive union of states spanning multiple time zones and climates. Perhaps if the US is compared to the entirety of the EU, then Congress and the American system of governing can be said to be one of the most impressive, if not the most impressive, experiment in government in history at that scale (although I'd much prefer Europe to the US even on average). But that's more a function of it being the only 300m+ country in the world that is also rich than it being the best among many of them.
Taking into context its size is a whole different matter, though. It's relatively easier to build an awesome small country (say the Netherlands where I'm writing from) than a massive union of states spanning multiple time zones and climates. Perhaps if the US is compared to the entirety of the EU, then Congress and the American system of governing can be said to be one of the most impressive, if not the most impressive, experiment in government in history at that scale (although I'd much prefer Europe to the US even on average). But that's more a function of it being the only 300m+ country in the world that is also rich than it being the best among many of them.