Out of the box, Poser has a much better renderer than Daz Studio -- IMO -- thanks to IDL. However, if you're not concerned with having beautiful lighting for final render and just need the shadows in the right place because you're going to sketch or paint the render, then Daz Studio will work just fine for you.

What you'll primary be missing in DS is dynamic clothing. I find dynamic clothing to be essential for non-nude portraits because almost all the conforming clothing -- except the stuff of the finest quality (and usually highest price) -- looks, well, not very real to me. Fantasy clothing tends to perform better, but I may just think that because I don't see people wearing armor every day. :D However, if you can live with the look of conforming clothing, again, DS will be just fine.

While I respect your opinion, and each person has their own eye when it comes to how an image looks when it is done, from a Technical standpoint both 3Delight and Firefly are based on the Renderman standard. The render engines are, technically, equivalent. DS has had IDL aka Global Illumination since at least DS 3. UberEnvironment2 Bounce (GI) is the way to make that happen in DS, though for most art, using AO correctly, is going to get you very similar results in a much shorter amount of time.  Further you aren't missing Dynamic Cloth in DS, though you are missing a way to create it. Optitex is the Fashion Industry standard software for draping cloth and that cloth engine is in DAZ Studio.