Aside from flavor, would shortening perform noticably different than butter in a cookie recipe?

Shortening has a higher melting point. That means the cookie will hold its shape better while baking. Butter will melt faster, leaving cookies flatter, and more spread out.
Unless you choose unsalted butter, using it you would want to reduce the amount of salt called for in a recipe. How much, I can’t say. If a recipe specifically calls for shortening, and not an either/or, I would say stick to that.
If you use butter, shorten your baking time, because thinner cookies will bake quicker.

@Patty_Melt -Thanks for the answer. It calls for butter but I can’t get it right now.

Speaking as a cookie connoisseur, I know when there is shortening in a cookie as opposed to butter, and I retain my rights to spit out the offending shortening-laced foul things.

@Hawaii_Jake -Foul, Lol!
I believe this and will do it the right way :)

I’ll be right over to judge the results.

@Hawaii_Jake Bring some tea with you, please.

@lucillelucillelucille I will bring an assortment including my favorite Darjeeling.

@Hawaii_Jake What would go best with lemonade cookies?

Assam

@Hawaii_Jake -Thanks. I will see if I can find that :)