That's a nice cross! You should get colored eggs of large size and they should be prolific layers as well. I have an ameraucana/brown leghorn cross. She's a sweet bird that lays a pretty blue egg. Depending on the heritage of the EE sire you could get pale blue or green eggs, but even a light brown is possible.
I found my mother's leghorns to be ill tempered, but that was back in the late 70s/early 80s. All chickens are individuals and you have good and bad birds in every breed (though I have yet to come across or hear of an ill-tempered araucana).
Here is a pic of my Lucky:
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