I think going from Poser 6 to Poser Pro 2012 would bring a lot of nice surprises.  It's hard sometimes to appreciate how well the program is maturing but then I remember I do most everything differently now than I did it then.  The morph brush is IMHO the single biggest non-rendering improvement since I started using Poser.  So easy to create morphs, fix poke through, smooth seams and creases compared to earlier versions.  That's the feature I'd expect will change your work habits the most.