The man are way faster in Berlin than they are in London, because Berlin is considered to be the faster course, even thought both are fast, and world records have been set on both courses.
The top elite women seem to prefer London over Berlin, and blazing times occur more in London than they do Berlin. But if Berlin is a fast course for the men, shouldn't it be just as fast for the women?
Also, from looking at the start list for the upcoming Berlin Marathon, Mary K, Tirunesh, Vivian, E Kipligat, and M Dibaba will not be there, so I imagine most of them are going to run Chicago, with Mary K running New York as usual.
The women seem to prefer London,Chicago and Boston or New York ( Mary K always runs that race over Chicago and Berlin), while the men seem to prefer Berlin, London and Chicago. The top elite women don't really get hyped about Berlin like the men do.