I can imagine that for some people it is difficult to understand why these housing estates are a WHS. Certainly many visitors think: What is so special here? That looks just like my neighborhood. But as Ian Cade wrote in his review: this should be taken as evidence for the success and impact of this architecture.
The housing estates are spread widely over Berlin, but I managed to visit them all in one day. But I had to start early in the morning and I spent much time in S-Bahn trains and stations. All estates have in common that they are very well maintained. Fortunately, the significance of the estates was already recognized in the 1960s and 70s and the buildings have been restored, in West Berlin as well as in the former GDR.
The modern concept of social housing differed significantly from the traditional tenement blocks. The building blocks were open at the edges, there were many green areas and courtyards. The apartments had a high standard with bathrooms and private kitchens and many of them have balconies. The estates are different in their style and appearance. The Hufeisensiedlung Britz is probably the most exceptional of the six estates because of its central structure in form of a horseshoe. Falkenberg is a suburban estate with terraced houses and gardens, striking are the bright colors of the houses. The other estates are rather urban residential areas. Schillerpark was the first modern urban estate in Berlin, with its red brick facade it reminds of the Amsterdam School of architecture (such as Het Schip). The Siedlung Carl Legien is closest to the city centre (near Prenzlauer Berg), but in my eyes it is the least rewarding estate. For me, the Weiße Stadt (photo) was the most interesting, maybe because the white cubistic elements reminded me of the Bauhaus style. Weiße Stadt and the nearby Siemensstadt (with the largest blocks) probably had the greatest influence on the architecture after WWII. However, in many of the later copies the principles of healthy and dignified housing are barely visible.
I am interested in modern architecture, but I must admit that from a tourist point of view this WHS is not very attractive (the whole day I did not see any other people taking photos). But I really enjoyed strolling through these neighbourhoods, eating a 'Currywurst' at a snack stall and drinking a local beer at a typical Berlin pub.
I like Berlin very much, mainly because of the 'mixture' of different architectural styles. Some recommendations for modern architecture: the government buildings around the Reichstag (and of course its glass dome), the Jewish Museum, the Holocaust memorial, and the quarter south of the Tiergarten with the Philharmonie (Scharoun), the New National Gallery (Mies van der Rohe), and many newly built embassies.