Many cassette decks had excellent Wow & Flutter and Frequency Response figures. For comparison purposes, I'm looking at a Denon DN-790R deck that had a specified Wow & Flutter measurement of 0.038% WRMS, while a Technics SP-10MKII turntable quotes a Wow & Flutter figure of 0.025% WRMS. Those figures are pretty darn close in my book, and impressive. Frequency response of the Denon DN-790R is specified (with metal tape) at 20-20,000 Hz + or - 3 dB. I see nothing wrong there either. The Denon DN-790R also featured Dolby B, C & S. So the quality did exist, if you wanted to pay for it. Direct drive cassette decks are still very much in high demand on the used market.