Popeyes ranks #2 on my list of awful slow service, thus my frequent comment that "Fast food is neither". I happen to like their crawfish, and once waited over 15 minutes in a drive through line for my order, and that is AFTER giving it to the voice behind the little speaker. It wasn't that they were busy, there was only one other car in front of me. I'll never know how long it actually took, because I finally gave up and went to pick my daughter up, later than I should have been.
#1 for crappy slow service is Long John Silver. And it's consistently bad at every one of their stores I've ever been to. No wonder so many of them have closed.
The best service I've ever seen at a fast food chain is Portillos. During the lunch rush, they send someone down the line with a wireless radio to send in the orders, The line always moves fast, and when you get to the front, your food is ready for you.