Because of the recent posting i'll assume this thread is still active. The PCU is a great cap! It sounds like a PIO cap with more resolution, focus, and detail, but with a natural, organic sound i've never heard from any other plastic cap. It may seem dark and rich because it's bass and lower midrange is so strong, giving the feeling of rolled off treble. The highs are there, but the ear will focus on the lower ranges more, giving the illusion of rolled off highs. It has a powerful "performance venue" effect, with great depth and space. This effect integrates the highs into the music, like sitting forty rows back in a concert hall. It may not work in some systems, or for all tastes, but if you crave this kind of presentation, you will be in audio heaven. The Theta is its little brother, and can't match the PCU in any area, hence the great difference in cost. It's the greatest sleeper among caps.