I'm very happy with downstream patches. They come 90% from Redhat, rarely from Debian or Suse. The Redhat patches are usually 100x better than other contributors patches. Debian is usually the worst.

When I maintained ~250 cygwin packages I acted as downstream also, and had to deal with upstream maintainers also. Usually a horror, maybe because I came from cygwin which was a crazy hack. Only postgresql said "such a nice port". For perl, gcc, python,... you were just a crazy one to be ignored.