The width of the magnetic gap on a record head has NOTHING to do with the performance of a subsequent playback head. The only compatibility concerns are those of track width, which in a cassette will cause severe crosstalk way before it affects performance parameters.
I have heard the "Nakamichi tapes only play back well on Nakamichi decks" thing for years . . . and I think it's an old-husbands' tale. But Nakamichis were more consistently in good mechanical and electrical alignment from the factory compared to most mass market decks. So if you make a recording on a Nak, play it back on the Nak and it sounds great . . . maybe in comparison another deck doesn't sound as good on playback.
Also, if you compare two tapes, one recorded on a perfectly-calibrated machine, and another on one that runs a tad slow and underbiases the tape, and play them both on a third machine . . . to most people the recording that's higher in pitch and sizzlier on the top end (the second one) will sound "better".
If you find a nice Nakamichi, buy it. They're great.
I have heard the "Nakamichi tapes only play back well on Nakamichi decks" thing for years . . . and I think it's an old-husbands' tale. But Nakamichis were more consistently in good mechanical and electrical alignment from the factory compared to most mass market decks. So if you make a recording on a Nak, play it back on the Nak and it sounds great . . . maybe in comparison another deck doesn't sound as good on playback.
Also, if you compare two tapes, one recorded on a perfectly-calibrated machine, and another on one that runs a tad slow and underbiases the tape, and play them both on a third machine . . . to most people the recording that's higher in pitch and sizzlier on the top end (the second one) will sound "better".
If you find a nice Nakamichi, buy it. They're great.