I'm thinking of upgrading from V4 and Poser 6. Which version of the Genesis models is likely to have the most longevity? (i.e. the largest selection of clothing and hair offered now and over the few years) Which version of Poser is likely to have the most longevity?

My frank and personal view is that so long as upgrading figures or models is a commercial business, there will be built in obsolescence. There may not be any so-called longevity in any particular line of figures. As for the software, well, the impact of divergence in supported figures has been very clear, with many software users being forced to make a choice of figures, or jump through many hoops to import content notoriginally created for that software.

I'd go for Poser 11 because I really like the comic book mode, but if you're ready to move on from V4, I would look at other options before committing to one of the Genesis models. You might start by experimenting with the free Sasha-16.

I would go for a Pro version of Poser.

Genesis 3 and 4 currently don't work with the DSON importer for Poser, although there is a utility that will allow models exported from DAZ Studio to be loaded into Poser.

The short answer is none.

The genesis figures have a roughly 24 month life-cycle. So far, they have had 3 different rigging setups and 3 different UV mapping systems. Each succeeding version takes more work to get working in Poser. I have several hundred packages installed. NOT ONE HAS POSER FILES IN THE CORRECT LOCATION. Not 1.

It is actually much easier to update V4. You can update her with weight-mapping, subdivision, and even add a facial bone equivalent.

This is the value of Poser - you have the tools to add the tech to any figure you like. You don’t have to either replace everything or drop a hundred dollars on conversion scripts.