I've only had rubbery, flaccid skin, undercooked disappointment from Duffs. Maybe they were well cooked before being submerged in vinegary sauce such that you have to go bobbing for wings. More likely, I was there at peak hours and they were never cooked well to begin with.
Deep frying is easy. Problem with wing places is dropping order after order of wings and fries into deepfryer lowers the temp of the oil. Colder oil means soggy, greasy food. In an ideal world they would wait for oil temp to come back up to optimal 350-375. When you've got a bar full of people who are ALL ordering wings, theres a trade off and you have to choose between letting people wait for 90 minutes or delivering a compromised product in a timely manner. At my favorite wing place back home (Richmond's) I've noticed it on many nights. Crowded nights, your mileage may vary. A quiet Tuesday night and they're about as good as it gets.
I think the above accounts for some of the discrepancy in quality. After moving to Texas I've also learned that some people just don't know wtf they're doing with wings.