All Nak decks broke but were able to be fixed. The consensus "best" was the Dragon. Three heads, azimuth alignment are the keys to a good deck.
You can buy them used but you may have to have it serviced. Once it is working as intended, it was considered the best back then and still is.
Now, as for TAPES, well, good luck finding the best ones--metal as I remember.
Cheers!