As mentioned by the OP, he already has learned poser, and is not concerned about ds being free, or purchasing upgrades to poser.

So his real question is what can ds do for me better poser cannot?

Rendering was mentioned as being better.. it is for displacement (as I mentioned) however poser's ao, ibl, and lighting system is still quite superior to DS.. as well as the amazing posr material system in place, which can even have lighting optimised by materials.

A quick visit in any bagginsbill thread attests to the power of poser's material handling system.

Also bear in mind, that the OP would have to totally relearn his poser content use switching to DS, and buy all the non free plugins for things poser can already do. (And Ds would still be missing things like dynamic hair and cloth.)

Also of note, Poser integrate well with Vue 6 infinite, and ds integrates better with carerra pro and bryce, so there's that difference as well.

I don't see totally relearning DS as much benefit over his familiarity with poser.

Way too many people take way too many things way too seriously.