In virtually all dimensions, Berlin transit is better than every US system, Except NYC. Which is ironically the only place Ive ever seen anybody pee in the subway, and that one is supposedly “protected” by turnstiles.
The US has a homelessness epidemic, Berlin has some problems in this area as well. This is a problem thats orthogonal to the transit system, and has to be solved by society at large. Turnstiles don’t solve homelessness.