I started with Poser 9 and upgraded later to Poser Pro 2012 because of the better use of memory. More than once Poser 9 stopped rendering at about 3 GB using of memory, while Poser Pro 2012 brought them all to an end without problems.

For example, in my Gallery you can find renders from the 'Bourbon Street Bar' with some characters, hair, highpoly clothes and SSS skin textures. For most of the rendertime Poser Pro 2012 used 14,8 GB to 15,4 GB of memory, so yes, the upgrade was a big improvement and well worth the money for me.

And especially because Poser Pro 2012 is still for sale for an unbeatable price I can only suggest to go for it instead of Poser 9.