I'm glad the Rietveld Schröder House is a World Heritage Site because not only is it an impressive piece of architecture, it also introduced me to the wonderful city of Utrecht. It is unfortunate photography is not allowed inside the Rietveld Schröder House, because the exterior does not do justice to the interior's inventive use of space. Downstairs the house is divided into rather traditional rooms, such as a kitchen and a studio. Upstairs, however, is an open floor plan which can be cleverly subdivided into rooms by movable panels. Gerrit Rietveld employed De Stijl principles when creating the architecture and furniture of the house, which give the house a clean, functional style. The Centraal Museum has an exhibit on Rietveld's furniture designs, and I'm glad I had seen the exhibit prior to visiting the house in order to further appreciate his work. There is much to recommend in Utrecht beyond the Rietveld Schröder House and the Centraal Museum -- I highly enjoyed the Dom Tower (which has incredible views), the medieval center of the city with its walls and churches, and the scenic Oudegracht, a canal in the heart of the city, when I visited two years ago.
Logistics: Although you can rent a bike or take a bus to get to the Rietveld Schröder House, I highly enjoyed the walk from the Centraal Museum, where the tour tickets are sold.