Seriously, I can't tell the difference between a duck egg or chicken egg. I've even had ostrich egg and thought it tasted like egg. They are all the same to me.
However, some of my customers claim that the duck eggs taste richer and have more flavor than a chicken egg. My taste buds are just not that discerning.
Hybrids like golden 300's and white layers. KC are a really close second, magpies, runners and welsh harlequins are good layers. My Cayuga is a machine and has only taken a few days off since Feb. She is molting and didn't do well in 100+ degree weather and has stopped for the time being.