Cycles to external renderer I have a model in Cycles, I am trying to use Mitsuba Renderer and just about everything goes wrong so far. I can give more precise problems I get, but there are just so many of them. Does it work out-of-the-box for you or is there some typical pipeline I should follow? Or do you just create all materials and things in the another renderer and never use the conversion? 

I also tried LuxRenderer, but it says it couldn't load pylux and pyluxcore. It still works somehow, but "Convert Cycles Scene" also spits out a load of warning and errors. So it doesn't look like it is doing to work unless I redefine just about everything in my scene.
Since there are no further answers: no, this doesn't work out of the box. Converter misses many nodes and some Nodes like "Light Path" are not possible to keep, if you want to use bidirectional path tracing. Node editor in Lux shows a warning sign near the nodes which were not correctly converted. To keep track of the conversion, one should run Blender in Terminal, as errors and warnings will be printed there.

Apart from that, many things can go wrong. The textures packed in .blend won't be loaded, multiple render layers are likely to be a problem.