Value: KFC's thighs are $1.99 each and weigh four ounces, while Popeyes's pieces are $1.49 each and also weigh exactly four ounces--an uncanny coincidence that makes us think of Frankensteinian genetically engineered birds that grow thighs to exactly that weight. In any case, Popeyes is a better value.
First impressions: Popeyes's chicken comes to you piping hot and very, very crisp. Nearly greaseless. If you attempt a bite, steam pours from the juicy depths of the thigh. It has that appetizing yet somehow unsettling fast food smell--like salt and MSG, in a good way.
KFC's thigh arrives lukewarm and with a growing grease spot developing at the bottom of the box. It smells just about the same as Popeyes. If you attempt a bite, the breading will come off all at once, and your hands will feel like an oil slick.
Crust: Everyone agrees that a crisp, well-seasoned, not-too-oily coating is key to good fried chicken. The crust on the Popeyes chicken is robust, seriously crisp, with a strange, rippled appearance that looks like crushed cornflakes. It's very salty and as crunchy as a potato chip, with structural integrity that lets you take a bite without all the skin coming off.
KFC's breading is pathetic. It's flaccid and weak, and will pull off in one grease-spattered bite. The supposed 11 herbs and spices are not discernible, except in a sprinkling of black pepper. It leaves a sandy residue on your tongue.
Chicken: Popeyes's flesh is juicy and (bonus!) tastes vaguely of chicken. It's also weirdly slick, almost slimy. But eaten with the crust, it's awfully tasty.
KFC's meat has an identical slick/slimy texture, a problem compounded by the lack of a crisp breading. It's reasonably juicy, and tastes fine, although it is absolutely drenched in oil.
This is a bloodbath of a smackdown, as Popeyes's fried chicken is superior to KFC's in every way, from price to taste. The difference in quality is so stark that if you are struck with a hankering for fast food fried chicken, it is worth traveling the extra distance for Popeyes. You might as well get the good stuff.