German cities themselves are definitely much nicer than American cities. In fact, "much nicer" is an understatement, American cities usually feel like they were designed by people who hate cities and want everyone in them to suffer.
That said, US lifestyle/culture has its own set of advantages compared to Germany. German culture is surprisingly backwards for consumer software/internet stuff, for example.
Salaries for devs in the US are insane compared to the rest of the world, I don't think they can be taken as a reference, especially as most people do not have an easy way to just choose to move there.