I think that if you are a user of a real CAD software like Autocad, Microstation, SolidWorks, ProEngineer, Catia... then it seems that you don't want to buy another one cause U don't need it. It seems that what U need is only a converter... or a different CAD software. I use Microstation to make plans and 3D models and , why not, to make renders too, cause if you spend so much hours you can obtain an almost photorealistic render. But I've found in Sketchup another way to express my ideas fastly, as when I drew with Pantone markers, pastel colours and gouache. But the best is that Sketchup can import/export kml/kmz files, and dxf files too, to work with Google Earth.
And the price is similar, but you buy a different Cad software that provides you others tools for working...

It's what I think...