Regarding paper in oil, they are great "audio" caps; as are film. Regarding the marketing hype, "no loss whatsoever in the bass frequencies" is, in my opinion, a bit of bologna. Perhaps it depends upon your definition of "bass frequencies." Good capacitors just do not pass DC. As they approach low frequencies, their impedance goes up. Period.
It would, theoretically, take an "infinite" value of capacitance to have "no loss whatsoever in the bass frequencies."
However, the price, ~$4.05/each after shipping, isn't as radical as some places and the caps are very good for audio.
That's my opinion, anyway.