Ah sorry, I overlooked that not everyone would know what they were. I think they are grown in the States, but - like here - aren't very well known.
They are of the apple/pear family, and fairly large in size, in comparison. They are generally not good to eat raw, even when ripe - a sour astringent taste and fibrous texture (there are exceptions with some varieties). However, they are really nice after cooking - peeled, cored and stewed, the white flesh turns pink and they have a slightly tart (but very nice) taste, and quite perfumed.
They are very high in pectin, so are more often used in preserving. Quince jelly is a fairly popular thing here, and is traditionally eaten with cheese, but it also goes well with meats like turkey. The fruit isn't very common here (UK), so most people probably come across (shop) quince jelly before they ever see a real quince. The Portugese for quince is marmelo, and that is where we get the word marmalade.
Another way to prepare quince is to blet them. This means laying them out in a single layer somewhere outside but sheltered. Preferably on newspaper or something. You don't want the fruits touching each other. A combination of decay and frost breaks down the flesh and makes them sweet and soft and edible. But it looks like you are eating something just this side of being rotten, which doesn't appeal to me. So I cook them instead.
I came in contact with someone in a neighbouring village a few years back who was advertising on Facebook for people to pick fruit from her tree (they are decorative, but not many people know what to do with them). That was my first time experimenting with the fruit, and I had fun. However, the encounter was not, so I never went back in future years. But since then I have bought "shop" quince jelly, and it is the secret ingredient in my pulled pork.
I now have my own young dwarf quince in a pot, which is too young to bear fruit, but I have plans to plant it in the front lawn, as I think it will be strong enough next year to transplant, and maybe bear small fruit in a year or so.
But by chance, these friends of mine mentioned *they* also had a quince tree, and needed to shift some fruit, so I was happy to take some off their hands.