For layovers this is a decent airport, but if you're staying in the Phoenix area, well that's a different story.
I was in town for a family reunion and a 50th wedding anniversary. I prepaid for a car rental at Budget. Getting out of the gate and through baggage was easy enough. But getting to the car rental area was a different story. All of the rental businesses are located in one building about 3 miles from the airport.
Shuttles run every few minutes but may be packed by the time it gets to your terminal. I traveled with 10 relatives so we basically took over the entire shuttle.
Coming back to the airport was a big hassle. Luckily we arrived 2 hours before our flight. We barely made our gate on time. The reason for the delay was the ridiculously long line at Security Checkpoint C. Our wait was intense and you could see frustration on nearly every passenger's face. 30 minutes is a long time to to be stuck in a line.
No one seemed to care about the line though, so I'm assuming that it was business as usual. If you're staying in the Phoenix area make sure you give yourself at least 30 minutes to get through the security checkpoint.
Or you'll miss your flight...