Hi SoCal,
I'm not so sure that the OGW Citrumelo is Swingle; That's why I mentioned the spherical shape. I may be misremembering, but as I recall, the Swingle is elliptical or pear shaped, not unlike a hand grenade, which may be their best use. The ones on my tree, on the other hand, were perfectly round.
As for taste, well, that is a subjective thing. They weren't **completely** awful, just unpleasant. They had an aftertaste with Sort of the culinary equivalent of fingernails on the blackboard, an analogy for those of us old enough to remember what a blackboard is. Also, I personally find grapefruits in general to be rather distasteful; I actually find the taste of Flying Dragon fruit to be better than grapefruit.