Left V5, middle V6, right a modified SP3.

V5 and V6 were subdivided using Poser's own subdivision. SP3 was not.

I'm pretty sure V5 and V6 bend better in Studio, but some bend fixes appear to be lost during the DSON import.
And while they of course still bend better than plain V4, they don't bend as well as a figure rigged especially for Poser can.
"One size fits all" rigging is another factor here, too.

The bending could be relatively easily fixed with some additional JCMs and weightmap tweaking, and that's exactly what I had originally planned.
But now I will of course rather concentrate on the new "Dawn" figure.

So, Genesis I and II do work in Poser if you really, really want to use them.
But they won't bend nearly as good as a "native" Poser figure can, unless you do some fixing.

Personally, I'll rather keep working on my own figures and of course I can't wait to give "Dawn" a try.

Would have been nice to re-rig and fix Genesis I to have its full shape-shifting functionality in Poser, but with the arrival of Genesis II, Genesis I feels outdated already.
And if I put work into a figure, I rather work with something I have the feeling it is the best available.
Genesis II on the other hand brings only very few improvements and it looses all the shape shifting ability that made Genesis I stand out.

The sculpting is a wee bit better compared to Genesis I, but the 2000 additional vertices don't really make a huge difference. To make her look as detailed as V4 or V3/SP3, you'd need at least 20.000 more.

Oh, and yes, V5 and V6's arms are definitely too short.This is not an easy fix in Poser, as the DSON importer breaks Genesis' scaling.
To fix it, the scaling blend zones have to be re-created and adjusted using the Joint Editor.