Thank you Hyfi and Joe!
To my opinion cassette decks and C-cassette are little bit underestimated equipments. I think there is two main reasons: 1. There've allways been low quality c-cassettes that make sound of any equpiment poor. 2. Practically all cassette decks were not tuned to work (speed, bias, EQ, etc).
So the experience of the cassette deck was in most cases poor since different tapes need different tuning (not only Fe, Fe-Cr, Cr and Metal, but different brands too). The best results without tuning of the deck were disappointing. Anyway separate decks beat any radiorecorder or boom box but you may miss in many cases the qualities of LP and later CD.
On other hand C-cassette should have been the most interesting vehicle to improve the sound by tuning and cleaning and taking care of. Anyway the magic of black vinyl is still unbeatable.