BIM.works Repository's main use is through it's API, but a UI is also provided.
More than a viewer
Quickly get all information of an object by selecting it in the 2D or 3D viewer.
All IFC attributes (also of IFC4 types), property sets, properties, classifications, materials, quantities are available. In BIM.works we call all of these together "features"
You can also quickly find all objects with a similar feature.