I've been living with my Utopia-terminated Prion for two weeks and am really liking it.
It did need some running in, sounded a bit odd to begin with, but now singing sweetly with 100+ hours on it. It is smoother than the stock cable. Not at all what you would expect from a silver cable, but very much in keeping with other dhc silver cables (as I understand it from other posts). It is more detailed than the stock cable, which might not be immediately apparent until you realise that the extra brightness and grain of the stock cable gives a false sense of more detail/air. At first, I thought the stock cable had more punch, but then realised that was because by comparison with the Prion it was a little lean sounding. Punch with the Prion is fuller and consequently not as attention-grabbing as with the stock cable.
I also have an adapter (dhc) for using my HD800-terminated Black Dragon with the Utopia. IMHO, That cable also improves on the Utopia stock, giving a warmer and richer sound.