If I was to be given a choice of tools, including commercial tools then I would probably go for Cinema4d as the interface is very nice as is the overall workflow.

I currently use 3dsmax but that is because I have to as this is what we are using at University.

If I were to choose between Truespace and Blender then i would probably go down the Blender route as I wouldn't be too sure as to what Microsoft will do with TS in the future. I personally think the UI on both applications could be greatly improved.