I had a Nak and it was beautiful sounding, but I also once had a $120 non-descript Harman Kardon deck that sounded almost as good. Won't reveal the model number as I'm currently scoping one out on eBay!
I owned a Nakamichi Dragon back in the day and I was VERY happy with it. Not sure if it was the best deck out there but it rocked my world for several years until I gave it away to a friend
The greatest ever produced? The old Philips one on my old Mk2 Astra car. Basically the road noise and looking at the road distracted me from all the sonic failings that cassette had. Domestic decks, even a Nakamichi would have only been used for making mix tapes to play on the Philips.
Funny, I was just talking about this the other day. I remember the whole thing about home taping killing music. To be sure I taped my share of LPs but I was still buying probably ten for every one I taped. Taping took time--at a bear minimum on a one-to-one ratio. It also took an investment in blank tape. You also had to be there. Compare that to what started to happen in the 90s with the iPod/Napster/file sharing thing. Incredibly fast downloading and functionally zero investment. I still see people today--mostly 20-30 somethings with thousands of songs on their phones and they haven't paid for more than a trifling number of them. Now we know what REALLY is/was "killing" music.
If it's just playback of old and pre-recorded tapes that you need, Technics RSAZ-7 from 1997 will shock cassette-phobes with it's excellent sound. It has an amorphous head that is very thin (was originally used for the DCC format) and tracks very, very well.
There is a story like this about the excess copies of the atrocious: E.T. The Extraterrestrial Atari 2600 cartridges.
RE" Nakamichi tapes not sounding good on other decks. Right now I'm listening to tapes made on my Dragon and CR7, on my Revox B215 (with newly installed pinch rollers) and they sound good. But... all the tapes that sound good are made by TDK. There is a difference but not to the point where it's distracting. The other tape that I have is a recording of Nina Simone made on NAC Cobalt tape and there is a noticable difference. The sonics are muffled across the spectrum. M~
Interesting bit of information.. I am now archiving metal cassette back up copies from my band masters, and a few surprises forgotten. (good original, unreleased stuff) The master tapes on Ampex 456 do not play, they have sticky-shed and have to be baked. The MXS metal tapes do play, so they are being archived first. They are being played on a Nakamichi 480 and do sound very good! This two head machine features narrow gap sendust heads. The only feature not found on most Nakamichi decks is a pitch control. Rather than mess with the adjustment on the Nak, I have a Sony TC WE475 with a pitch control for the few tapes that need this adjustment. The Sony is a laugher, but the transport isn't too awful, (no azim drift) the heads good enough, and circuitry to produce playback very close to the Nak 480.
Speaking of metal tapes, I still have a dozen of TDK or Maxell metal cassette tapes in shrinkwrap. I suppose the sound quality difference between a Sony and a Nakamichi should be minimal if metal tapes are used in both decks ...
Believe or not, the parent company of Tandberg Audio, morphed into a tape-drive and video-conferencing equipment company and was subsequently bought out by the American networking giant Cisco ... OTOH, I think Nakamichi just disappeared. It fell on hard times and some Chinese company bought it out in the mid to late 90's and that was the last I heard of that storied company.
The Harman Kardon CD 491 cassette deck was tested against the Dragon back in a 1988 cassette deck shootout and blew the Dragon out of the water. I had one years ago, amazing sounding deck, sadly mine died.