To be perfectly honest ... I hate going back to P4, as much as P5 frustrates me, the library management in P5 alone is worth it. I only use p4 when I need to import something into Vue. Now with SR3 it is very stable ... well, as long as you stay away from the FIREFLAW renderer. I only use it when I absolutely have to (like for 3d motion-blur, or certain materials/shaders, and reflections.) Even then I think very carefully whether I REALLY need/want those effects. There are still a bunch of problems, annoyances, and feature sets that have not been addressed since version 3 ... yes, version 3. I guess that is what is so frustrating to many of us.