I basically have the same questions about Houdini.
But there's one thing I know through some research that I did recently about Houdini's rendering power, that its rendering quality is at the top tier amongst other s/w packages. Because Houdini lets you select your choice of renderer either of its own or the RenderMan. Its direct integration with renderman lets you access renderman's shaders as its own - this way, you can use renderman without actual programing.
Ain't it sweet??? And also, I am not too pleased with Maya's renderer.
Another point; I'm sure you know that its particle system is second to none!!!!
ANyway, any information regarding unanswered topics would be greatly appreciated...