Clark L. Coleman wrote:

I have seen online reviews of particular cassette decks that claim
that Dolby C makes for bad-sounding recordings, especially on high
frequencies. Example is Harman Kardon DC520 cassette deck.

I have only used Dolby B in the past but need to replace an old broken
deck. Is Dolby C good on most modern decks, but bad only on a few? Or
do people complain about it in general?

What's more important than what type of NR you have, is the number of
heads. If you're using cassette, get a 3-head. I've never heard a
2-head that didn't sound bad, compared to a good 3-head.