Never used it and I can't imagine I ever will. A friend uses his on occasion so that he can listen to some "learn while you drive" tapes that are only available in that format. I've also heard some people use it to hook up thier mp3 players. However, I'd be happy if cassettes would vanish from the face of the earth. Same goes for ash trays in cars.
It was three days before I knew it was there. At least it is covered up. I agree with those that would have some outlet for MP3 or hard drive loaded with whatever kind of music you wanted. Very old Technology but does cover all the bases. When I can go from AM to FM to CD to XM to Cassette it is hard to ask more.