Neither really, I went with them based upon the available reviewer/user consensus that they tended to speed up attacks and leading edges, while also providing more detail and better decays.
I'm also aware of the consensus viewpoint of Stillpoints being absolute champs of holographic imaging and soundstaging, and certainly those values are important ones as well. In my case, i.e. specific to my system and my priorities, I felt I was doing well enough there and went with the Star Sound platforms for their claimed virtues.