This is not from personal experience but the impression i have been given by car shows (read: Top Gear, always spiced up for entertainment value!) is that American cars have terrible handling and spongy suspension, likely due to necessity with there being more winding roads in Europe compared to America. American cars appear to be build for straight up 1/4 mile speed and long comfy cruises on the highway. Considering that you are looking to buy a car to use in america however, there would likely be fewer situations where handling would be an advantage. They also always complain about the materials, fit and finish of the interior of American cars but that is likely subjective.
The US has a
huge road network that traverses every kind of environment imaginable, from the fully tropical to full-on arctic. The quality of our roads are highly variable. Some are beautifully maintained, some are gravel and dirt - and everything in between. Also, the economic rise of America (roughly) coincided with the advent of the automobile. Americans are more used to plentiful affordable cars and treat them as a much more disposable possession than Europeans do because of the higher cost of vehicles and vehicle ownership in Europe. The presence of huge interstate highways means that Americans spend much more time cruising a medium speeds on bumpier highways.
All of this leads to a preference for a relatively cheap medium to large-sized car with more suspension travel that is more softly sprung than most European cars. To Europeans, that means we drive big, dumb, wobbly cars. True in a sense, but a stereotype nonetheless - nor does it mean that many European cars aren't tinny, bone-shakingly stiff little runabouts. The huge numbers of sports sedans, roadsters and other sports cars that we import also show that we love corner-carving, stiffly sprung sportscars too.
The only thing that comes to mind that is more factual based is that there is a big push towards economical cars in europe. There is a growing selection of cars hitting reaching 80MPG and having test driven one, I noticed very little performance tradeoff compared to your average European car. You will have to use your own knowledge of the american market to compare this to American manufacturers.
Cost are higher in Eurpoe, so your average European wants a more durable, economical product. Also, you must remember that "MPG" figures in Europe generally represent miles per
imperial gallon, whereas American MPG figures are stated in miles per
US gallon. An imperial gallon is 1.2 US gallons, meaning that unless you convert the numbers and compare them directly, European cars seem to get an unfair (and nonexistent) 20% boost in fuel economy.