Here is the quote from the cider workshop.
"I tried a small batch a few years ago, roughly 70:30 proportions apple
to quince pomace, because I had the quinces. Can't remember any SG
details, never measured the Ph.
The resulting cider tasted very odd indeed, not exactly unpleasant but
not exactly nice. It had a weird slight chemical overtone best
described as tasting like the smell of paint. It matured slowly to a
more palatable flavour over a few years, but I'd not try it again.
In summary : Quinces - IMHO good in apple pies, not good in cider. "