"The list, released on Jan. 28, ranked the nine largest U.S. airlines based on their performance in 2021 across seven categories: on-time arrivals, cancelled flights, extreme delays, tarmac waits longer than two hours, mishandled baggage, passengers being involuntary bumped from flights and customer complaints."
Since delays are one of the factors I can see it, since Ft. Lauderdale is one of their hubs. Those afternoon thunder storms can mess up their whole operation.
Even with the delays they're still a better experience.