Of my original 10 chickens, both of my Easter Eggers are alive and at least through last year, productive- we'll see if they keep going post molt this year - never a problem with either of them. The other original hen is a Speckled Sussex.
One of my customers had a house guest (pre covid) who had stopped eating eggs because they made him ill - they talked him into trying mine and he felt fine (and enjoyed them!) Hard to know what the little differences are.
I breed for both egg color and egg production and longevity. Naturally they all look the same once you crack them into a pan, but my favorite moment is finding out what color a pullet is going to lay - like Christmas multiple times a year.