I grow Easter Egg since 2018 and I can't tell you much about the hardiness because it's in a large pot and gets winter protection. I do not like the very ruffled ones very much but this one I saw flowering in a friend's garden in Italy and there it was extremly beautiful and distinctive - so I got me a piece of it.
If you look at the pictures you only see a big ruffled flower - if you see it in a garden (depending on light conditions, especially in the morning) you can see a bluish neon-like hue on the lavender violet colored parts of the flower. This is a quite rare trait that I like very much (I have only two other cultivars that show similar effects).
I've taken many pictures to catch this effect - this ist the best, even if the flower is not the best I've ever seen on this plant