Southwest is by far my airline of choice, especially when traveling on the West coast.
Friendly employees, modern planes that are clean and sporting on-board DishTV and internet. Can't go wrong!
The Southwest counter at Phoenix Sky Harbor is large and has plenty of employees working the check-in machines. One feature I greatly appreciated was a separate baggage line for those of us who have already checked in with our smartphones. It was nice not to have to wait for travelers who were checking in just so I could drop off my luggage.
The Southwest terminal is a bit of a journey from check-in, but not as bad as some other airports in major cities. (Nothing is as good as Burbank (BUR) as far as walking distance but hey, it's a tiny airport.)
Overall, Southwest Phoenix Sky Harbor gets 5 stars!