Duck eggs are like chicken eggs, but some say the taste is stronger. Scrambled is better then fried, the texture to me, is more rubbery!
I bake with my duck eggs, and I use 1 duck egg for every 2 chicken.
I do not like to eat the duck eggs, myself, but baking with them makes breads and cakes so much better.
I also use them in meatloaf and meatballs and find no taste difference.
Some people that are not able to eat eggs, can eat duck eggs.
I have never tried other poultry eggs, besides chicken, duck and goose.