I haven't tried the Dusky, but I'm a firm believer of heirloom vegetables and flavor. There's a reason they survive generation after generation, a reason why people grow them.

Hybrids are inbred (a process called 'selfing') for several generations. They're bred for disease resistance, pest resistance, for harvest all at one time by mechanical means, for uniform size, shape, color, etc. What do you lose in all that? Flavor! After all, that's why we grow our own produce, right?

I am just kicking myself about this! I think the only reason I switched was the Prosperosa didn't produce long and certainly not until frost. My sis told me all she ever raised was Dusky, produced until frost, etc., so I tried it.
The Prosperosa probably died of neglect....it was in a hidden spot and I didn't get to it often enough.

I would rather have a few delicious than a bushel basket of bad!

I agree with all you said about heirlooms.