Hi Sebastian, also a fairly new renderer that several people here have tried out and liked is Simlab Composer: http://www.simlab-soft.com/3d-products/simlab-composer-main.aspx , their rendering-only edition is $149.

For exporting to Simlab you may need to use OBJ format with "Quads & Triangles" output rather than n-gons though. But n-gons are not required to get a good rendering, they're more of something that are nice to have just to keep the wireframe nice and tidy. Support for the vertex normals is much more important for getting a good looking final rendering.

- Michael