I (my company) am actually using PhotoWorks with very good results. Sometimes the results are frustrating and time consuming but we are producing some very nice renderings. Before settling on PhotoWorks we demoed some other packages. It really comes down to what you need for features and the price you want to pay. The SW website has some rendering partners on the solution partners page. One that comes to mind is
they offer translation and rendering software for SW. There is also another company on the solution partner page "ART" they offer a very high end rendering software/hardware package.
Something to remember if you're not using PhotoWorks for rendering SW models then you will need to translate your files into another format so the rendering software can read them. This typically breaks the link between the rendering file and the SW file. Meaning any changes to the SW file don't update the rendering file. One of the biggest reasons we use PhotoWorks is because of the file link and compatibility guarantee. I believe Okino and Alias have translators that actually keep the link between the rendering and Sw file? You could also have translation problem.
As far as rendering specific software...there is lots out there. Lightwave,
3D Studio, Maya, Okino, Alias, Blender are just a few off the top of my head. They would all work with SW files with some sort of translation.