Well .. After some problems with the latest version of Mitsuba, I returned to work with exporter. Apparently, the SSS shader improvements have been substantial, the result has been raising the quality and improving the render speed.
I'm glad to see the render plugins are still progressing. The result you got there is already looking good. I would love to get some high quality textures with normal, displacement and specular maps available soon, so we can improve our renders a lot. Keep up the good work! They are really important