The demise and disappearance of Delta brakes coincides with a couple of things - Shimano perfecting the mechanically superior dual caliper system in the early 90's and Campy deciding that they wanted to keep up.

The Deltas are fine brakes - I don't have a single issue riding on them. They have plenty of stopping power and have a great feel for feathering and modulation.

That said, they truly aren't in the same league as a good set of dual calipers.

55/Rad