All he said and more. Great layers of huge jumbo eggs that keep getting bigger and bigger. The most economical chicken for egg to feed ratio. One warning, mine like sleeping in trees, and will poo on the cars and anywhere else they take a notion to go. And they are known to roam long distances like Rhode Island Reds. I've caught mine headed down the dirt road going to town an 1/8 of a mile from home. Leghorns will tolerate being penned up but are happiest foraging. If they ever taste freedom, they will do every thing under the sun to escape being penned up. They are like little Houdini escape artists!
PS handle and pet them plenty regularly from the time they are little, otherwise you'll be lucky to ever get hands on them.