Doesn't the US have, unequivocally, the best higher education system in the world?
Admittedly, our lower education can be utter trash at times.
It's a bit more complicated than that.
While it's absolutely true that the US has most of the absolutely best universities in the world, you can look at the UK which also has quite some if you take into account the population differences.
I would guess that the variance of quality of education is higher in the US than in many other western countries though. (or maybe not, just basing this on what I know of the Nordic countries...)
And if you compare a 4 year university education in the US and in Sweden, they are very different. If you would go to a business school in Sweden (which used to be 4 years, now pretty much everything is 3 year BSc + 2 year MSc), you only take classes in business/economics/etc (unless you take extra classes in other subjects).
This usually means that an average person coming from the US to Sweden after only 4 years of college would most likely not be as qualified as his/her Swedish peers in the field.
That's what I've heard about Swedes going to an average American university for 4 years and then coming back.
You have to remember that's it's probably more common than not to take a year off, or even more, after you've finished your lower education in many countries, such as Sweden. So this doesn't mean that Americans are less qualified at a certain age at all.
However, If we look at
higher higher education I'm pretty sure that the US would qualify as the absolute best.
Quantifying and comparing higher education overall is probably a lot harder than lower education.
edit: Correct me if I'm wrong on anything, some of it might just be speculation.