There are still a few reasons to go, I am expecting rigging (maybe weightmaps) to be one of the reasons to upgrade. How many poser users are scared to go into the joint editor as simple as it is now?  When poser adds weight maps or something of the like, how many users are going to be willing to go back to the library and start rerigging all the products they have?  If poser gets too complicated how many people will drop it for Daz Studio bare version for simplicity?