I posted this on facebook but since not everyone is on there I thought I'd share it here too.
In Switzerland, we have this Citrumelo called Nr. 82 because that is its catalogue number from Eisenhut nursery. It is a selection they made. It is not known what the original variety was. A fellow citrus enthusiast once said that this was by far the best Citrumelo he had ever tasted and that he thought it tasted like a grapefruit from the 80s. A few days ago, I picked the fruits and I have to say it is quite good for a Poncirus hybrid. The flesh is sour but with a notable sweetness. It is also bitter but not unpleasantly so. And there is very little poncirine taste, no resin. The juice is even better, I can drink it just like that, bo Poncirus notes whatsoever. I used the juice to make jelly and I think it tastes great.
Mind you, this is still far from eatable compared to any commercial citrus but much better than other Poncirus hybrids that I have tasted. It is also better than Dunstan in our climate. I have a smaller one in ground but it hasn't fruited yet. It did sail through its first winter with about -9C unscathed though. Considering that spring and early summer were much too cold (everything is about a month behind) I think it could taste even better in a normal year.