Cassette decks polarize people. There are many who find the format outdated in technology and sound quality, while others praise how far it has evolved technologically during its hey day and the sound quality it can produce.
The problem with the format is that it is delicate and fragile. It takes very little for a deck to go out of alignment. I would estimate that about 90% of cassette decks (full size components) owned by people are out of some sort of alignment within the first 5 years of use. And if that isn’t bad enough, the inter-comparability between different makers wasn’t always spot on. All this contributed to giving the format the reputation of being poor in sound quality. And in contrast, by the mid 1980s the format was at its peak in terms of sound quality and technology, fueled by the likes of names like Nakamichi, Revox, Aiwa, Teac, Tandberg and a handful of others.
For those of you who dismiss the format as poor sounding, you owe it to yourself to experience a fully restored TOTL model from the above listed makers. You would likely be floored. Yes, the format has limitations such as a higher noise floor and a more limited frequency response. Even the type of blank tapes used play a monumental role in a deck’s performance. However, the noise isn’t audible with most music unless the passages are very soft or you are in between songs. Frequency response of the better decks easily exceeds 20kHz if the tape is of good quality and if the user knows how to calibrate and record - this latter requirement is critical and in my experience too many users just don’t know how to execute this step properly, resulting in a less-than-ideal recording.
It is a fussy format for sure, but a huge amount of R&D has been invested in it, bringing its performance to an astonishing level. When I used to work in retail, Aiwa and Nakamichi were amongst the kings of decks. A user above mentioned the Aiwa F770 and F990. Those two models, if in excellent condition and fully restored can amaze you in just how incredibly good sounding they can be, coming within a hair of the State of the Art Nakamichi Dragon, ZX-9, 700ZXE and the all-mighty 1000ZXL, the king of all cassette recorders.