I love sketch up and have been using it since it came about. However all the way through college i got lower marks because my sketch up models could not compete with 3ds max combined with v-ray. 2 years have nearly passed and i was wondering if there was yet an easy to use renedring program/add on for sketch up?
Well if you like the results from Vray then there is a plugin for Su.
http://software.asgvis.com/index.php?option=com_content&view=article&id=297&Itemid=199
I have found Twilight to be easier to use (and cheaper) but I am in no way an expert at PR rendering.
http://www.twilightrender.com/
There are others but I cannot comment as I have never used any of them.