VizUp Streamline enables you to reduce the number of polygons in a complex 3D model while retaining the quality and appearance of the original. Supports Wavefront .OBJ, VRML2 and StereoLitho (STL) file formats.
I found using VizUp very easy and very intuitive. Good visual feedback of how far you can push the polygon reduction, and a sophisticated algorithm combine to make polygon reduction a breeze. It will be even better when you can 'selectively' reduce different parts of your model. Highly recommended.
VizUp is a great polygon reducer and a terrific bargain. The single model mode, using a very clever and original interface, allows us to instantly see the effects of any compression level and choose the one that meets our need.
You have the best 3D decimation out there by far for the price and I have tried high and low end software from all over the world.