Sky Harbor can be nice or awful, depending on where exactly you are. The terminals vary widely in amenities and food options offered, or so it's been my experience. The airport is pretty well labeled and it's easy to figure out where you're going. The doors are well labeled so if someone is picking you up at the curb, it's pretty easy to tell them where you're at.
They've upgraded there rental car facility and it's pretty nice, even if it is off the airport kind of. The airport itself is a bit frustrating to drive through since the signs for the freeways can be confusing. As someone who lived in PHX for a number of years, I get annoyed by their freeway signs and always end up confusing myself.
Overall, it's an ok airport. I've seen a lot better and a lot worse. I find myself here often and would like some improvements - like some more options put inside certain terminals - but I'll survive without them.