The rendering is improved so much that in my opinion you will stop using P6 once you have used P7. It will now render scenes that were impossible to render before.
Add the morphing capabilities (to fix those poke throughs) and you have a very good and stable environment to render.
Of course there are still a few problems (I'm sure most of these will be fixed with SR1). Most of the problems have no impact on rendering and limited impact on other things.
Overall the current software is very stable and a major improvement over previous versions.