I have both Ares II 8-wire and Eros II 8-wire, which I use mainly with my Phantom. I have reviewed the Ares II 8-wire already (
link), but my Eros II 8-wire review will still take a while so these are early impressions. Ares II 8-wire is a "grand" sounding cable with quite a bold presentation and it works really well for vocals, which become strong and at times eerily realistic (like a whisper in your ear). It stays within the tonality of the stock Ares II, adds tons of air and expands the stage. I found that when I listen to classical music, it gives a real sense of the venue, like I am sitting in a concert hall.
Eros II 8-wire by comparison is a more refined cable with much more subtle qualities. It reduces some of the warmth of the Phantom, but does maintain excellent timbre. It improves transparency, more details come through and I personally find that the stage feels deeper and more airy to the point that it almost feels like I am listening to an open-back. I don't think it necessarily lifts the treble, but the more neutral tonality helps violins to come through a bit better, as well as the sparkle from cymbals, but the treble does maintain the typical Phantom smoothness. Imaging is really impressive and while it does not give the same sense of sitting in a concert hall as the Ares II, it has its own charms that I have become quite addicted to. The layering is just so beautiful and precise.
So Ares II 8-wire is a warmer and more exciting cable, whereas Eros II 8-wire is more neutral and refined.