Everything mentioned above (plus it just operates smoother), but unless I missed it, how can we leave out my big wishlist item since P4 ... OPEN GL PREVIEW SUPPORT!! 

Also, if you're an animator this helps with rendering preview movies (which are essential if your serious about animating) as it utilizes the Hardware OpenGL functionality of your system to speed up the render process. 

I was a very disgruntled P5 "beta-tester", and I was very hesitent to get Poser 6 because I felt ripped off by Poser 5 like many who purchased it, especially early on.  However I could never go back to Poser 5.

Still waiting for multiple-undos, better dual-monitor support, and various other upgrades that are overdue, but all-in-all major improvements through and through. (memory handling, items staying un-animated, etc., etc.)

Hope that helps too!

Best,

Tim