People considering Rendering Engines for SketchUp often wish that they could compare renderings of the same model with the various engines. We placed some models on the 3D Warehouse and invited people to download them and render them and then post the results to SketchUpRendering.com.
You can view the results on these pages:
If you need a rendering plugin you can try IRender nXt for 30 days for free.
All of these models are stored in this Sample Models for Rendering 3D Warehouse Collection