I probably had some kopi luwak, twenty years ago, in a restaurant. James Hoffmann explains why I say I probably drank some. Even twenty years ago, ("someone told James that") four times as much KL was sold than was produced. Hoffmann also suggests that it would be better for you to eat and process your own green coffee in the same way that civets do. That way you aren't contributing to animal cruelty, and you can be certain that you're really drinking coffee that has actually been pooped.
My memory of the kopi luwak is, that it was unusually smooth and gentle. It was a fine cup of coffee, supremely inoffensive, perhaps a little boring. Compressing the flavour experience that is coffee into a one-dimensional line for easy comparison, the probably kopi luwak I tried was, I don't know, mid-range. Very drinkable. Beats diner coffee. Doesn't hold a candle to most well-made specialty coffee.