Actually, the first cassette I dropped into this deck was a live-to-2-track recording I did about 20 years ago of a Ph.D candidate performing a piece for berimbau. It had been stored in a hot Texas attic for the past 10 years, and it's storage during the previous 10 years was not much better. I was actually surprised how great it sounded (not to mention the fact it was recorded on a Nak and played back on a Pioneer). Very little hiss. Decent dynamic range. Good frequency extension.
However, the 2nd tape I tried did sound pretty bad (sonically). A bit of a hot mess. It was a pre-recorded cassette released on the 4AD label (one of my favorite labels).
Neither of these examples should be proof of the quality of the cassette format (or lack thereof). Quite frankly, if I wanted to get as close to that "live" sound as possible, I'd listen to myself play guitar.
My desire for a cassette deck is for access to music *in context*. By this I mean finding "mix tapes" from back in the day, and reliving those good times through that particular sequence of music. Back when one was lucky enough to have a boom box with both detachable speakers and a dual-cassette deck. Back when some songs were recorded from the radio. Back when CDs were emerging from being a novelty. Back when you had to think about the next song while the current song was playing. When a mix tape was an art unto itself. Back when you recorded your friend's brother's LPs when he was back from college for the weekend.
It's more than just nostalgia. It's about the music.