DS is not free, only the base is. It is more expensive than Poser now and still does not have all that Poser has, for now. That is supose to change but with more bucks.

If you don't create content then DS is a good option All though there are those that still have problems running DS. 

I thought I read on the poser blog that there was a poser 7.5 or something like that, coming out besides the pro version. I will be looking at the pro version myself for the render nodes and 64bit.