What's the best American car?
American cars aren't even made in America. Everything you buy is a collection of parts from everywhere. Everyone has factories all over. I know now of no 100% manufactured and assembled entirely in the United states. There are too many categories with different winners to declare a best, everyone has pros and cons and longevity and reliability are honestly similar comparing new cars. Foreign or domestic, economy or luxury you will get what you pay for and all have maintenance and break. There are as many Ford Mechanics as Honda. It's a question with no answer.
I can't believe no one has mentioned Tesla, designed and built right here in the USA. Tesla's have exceptional owner loyalty and for good reason: quality design, advanced technology, and thrilling performance. For a while there, they had a market capitalization above General Motors. The stock market is indicating where they see value for the future.
"The best" is going to depend on a variety of factors, but if I had to choose it would probably be the Cadillac CTS-V followed by the much more reasonably priced Chevy Impala, or maybe even the Ford Fusion with the right optional powertrain. The brand new redesigned Buick Regal lift back in GS form with AWD looks like it could be serious contender as well,
I've rented a lot of cars. The Chevy Impala is a horse no foreign car in its price range can match. Comfort, power, room and a modern dashboard. These cars are built for today, but also easily will make the 200,000 mile mark for those seeking durability and value.
Haven't shopped new but I just bought a 2005 mercury montego luxury. Love it. Made in Chicago. Drives smooth and has some upscale features. When I replace it in few years I may buy a slightly newer one, maybe a 08 sable, same car rebadged for 08.