Funny you should ask. The Sig 3 has slightly deeper bass and is more natural sounding in the mids, it just sounds more real. I tired the cords in two different systems on a Pass X-250 SS amp and a Graaf 5050 tube amp with the same results. I would buy a Sig 3 for the used prices and put one on my amp. We also tried using the non EPS-3 on the CDP but the combo did not work well at all. Too much of a good thing as it sounded a little slow. I tired the Sig 2 on the CDP a long time ago with the Sig 3 on the amp but did not find the Sig 2 added any real improvement at that time, in that system. If you only have enough scratch for the non EPS 3, buy it and don't look back.
Happy Listening.
Happy Listening.