GNUstep is a development framework in the first place, not a desktop. There are however some related projects to provide desktop applications based on GNUstep.
Backbone is an attempt at creating a Really Good Desktop.
Étoilé intends to be an innovative GNUstep based user environnement built from the ground up on highly modular and light components with project and document orientation in mind, in order to allow users to create their own workflow by reshaping or recombining provided Services (aka Applications), Components etc.
The GNUstep Application Project seeks to develop a comprehensive set of administration and user level tools to make using the GNUstep environment a very pleasant experience.