The main advantage of Genesis is the unimesh feature. Compared to WM V4 the WM features of Genesis are a bit better but not as significant, for many users, to inspire a jump. Others might feel that the joint system is a big improvement that justifies the update. It depends on how you use the model.

The unimesh feature though is nice. The ability to dial morph from several characters opens up a lot of possibilities. There is also better UV map support, although I'm not sure that that feature works in Poser yet.

Of course for Studio users there is the advantage of having Genesis pre-loaded with the application so, cost-wise, it's very attractive, now that V4 is a paid product. 

Hope this helps.

Paolo

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