At some level DSP does degrade the audio signal, but in well designed equipment the amount of degradation will be insignificant. BTW, TACT is not exactly telling the truth when they say there is NO distortion. The repeated division of a digital binary numbers will ultimately result in a product that exceeds the processors bandwith and some portion of the digital word will be discarded. This "rounding" error is a type of distortion.
As with any type of signal processing, you need to balance the benefits of the processor vs. the added complexity to your system.
As with any type of signal processing, you need to balance the benefits of the processor vs. the added complexity to your system.