Aw man...P5 is a huge leap from 4. Adding dynamics, real hair, and cloth. but the biggie is shader nodes. Which P6 improved on with the Toon Shader. Not to mention the ability to "bake" your shadow maps, keep your textures loaded as you build your render. both of them have flash export. face room, and easier joint creation. I'm looking at PC boxes too. They seem to play better with the software I like.