I've traveled a lot for food, and, despite not living and never having lived in America, the US has the best "foreign" food I've ever had. The best Chinese food I ever had was in the US, for example. In fact, I think high (and high-ish) cuisine in the US is generally quite good (despite crazily sized portions WTF).

I've had incredible Korean food in random towns (~20,000 pop.), incredible Indien in another (<50,000), etc.; I think the US is kinda special when it comes to foreign food like that.

And, of course, there is some American-American food that is amazing. The greatest filet mignon I ever had was also in the US (and again, random small towns, not metropolitan cities). Also: donuts (not from chains) can be craaaaaazy good. Also cheesecake, though I actually prefer the German version of New York cheesecake (cheese cake is originally German, New York improved it, then Germany improved that).

The problem is grocery store food. It all has 3x sugar and chemicals compared Europe. Literally everything, sometimes even organic stuff, tastes fake and disgustingly sweet. It drives me crazy, and is one of the top reasons I would never live in the US. I also dislike the espresso there: nearly all specialty coffee I've had in the US has either been extracted by untrained barista or has been a bad copy of faux-skandinavian roasts. I think that situation is better in larger cities though, which I've spent less time in.

Ok, sorry for this very, very long ramble. Just some thoughts on American food from someone who didn't grow up there but has tried a lot of it.