Poser 5 is Poser 4 with some new stuff piled on top. The core engine is the same 1999 program we've been using for years and even that was/is buggy. But instead of fixing the underlying structure like they promised, CL focused on adding frills. So P5 users are driving a Model T with air conditioning, CD player, and power windows. IMO, P4 works better and faster on the same engine because it doesn't have the added weight of the new "features." Want proof P5 is P4? Simple...it has the same bugs we've been bit*hing about--and CL's been promising to fix--since 1999. What coder in his/her right mind would rewrite a program but make sure the exact same problems were included? Even things that should have been easy to fix weren't fixed. Until they fix the old, crumbling foundation, Poser will never be what it could be (or what was promised). Even if it works.