I own P4, P4 ProPack, P5 and now P6. Up until April4th, I used P4 with ProPack only, as I really disliked P5. I was very surprised and happy when I did get P6, and that is what I will be using from now on. I have connected the libraries, or what-ever you call it, and everything that I have in my P4 library works perfectly in P6. I haven't tryed making a very large render, the one's that everyone is saying causes a "memory" problem, so I can't comment on that. I usually, Pose in Poser, and then Render in Vue. (: