They are a high-quality cassette at an affordable price. They operate quietly-without any squeaking or mechanism chatter, and are fantastic for recording wide dynamic range sources such as CD's. They have minimal hiss without the use of Dolby, and I've found that you get a superior reproduction across the frequency spectrum with a hiss level that isn't bothersome when leaving the Dolby B or C switched off! They record well past 100% modulation (up to the +6 level-in the red) without any discernible harmonic distortion. That's nice, since many cassettes of other brands do "crap out" easily. I highly recommend this cassette brand to all users of HX PRO decks.
I find these cassettes to be the best performing out there, The other one I suggest for serious audio recording are: The slightly earlier series with the black and red lettering on the package.