It can import and export in OBJ format.
The latest version of gSculpt has the new draw face and draw quad mesh tools. AFAIK, they are somewhat similar to the pen tool in Modo and the new Retopo tools in Blender 2.43. They allow you to create polygons by drawing them, using an existing mesh as a shape template if you wish. They are demonstrated in a video tutorial available at the gSculpt site.
gSculpt is completely procedural, meaning that the procedure required to build a model is stored in a project file. This procedure can be explored, allowing you to see how a model was made by the artist. You can try this with the example files that are supplied with the main gSculpt package.[...]"