One of the probles with some quinces is that they remain very woody next to the core, which can be quite a large proportion of the fruit, so the best quality ones have a small core relative to flesh which makes preparing them before cooking much easier.
I cut one open, and it was quite easy. The core is small in relation to the flesh area. However, this one had bruised internally without showing any sign externally.
The tree has only been in about 3-4 year, so cropping is very light, half a dozen fruits of varying sizes.