Easy check in & check out
Gold members can go down stairs to the lower level & hit the "gold members" counter if need be, or not! Simple pick up/drop off that is very easy and doesn't have long lines.
The vehicles I've rented have always been the cheapest- I'm usually there for work after all- but even with reserving the budget vehicles, they've always had the latest tech. Blue tooth, easy to use navigation that either pairs with my cell phone or is existing in the car. The Kia I rented recently, really impressed me. I mean, it's a budget vehicle- a Kia! Not something I generally equate with being "high tech" but as soon as I paired my phone the nice large screen in the center dashboard paired with my iphone and displayed my "Apple maps" with navigation. Loved it! It made is so much simpler to get around the city.
Also the car was very clean. They did a fantastic job maintaining the interior, you'd think it was brand new instead of having 28k+ miles on it.
I had a hard time finding the rental car return the first time I returned a car here because it is a bit of a trek from the main airport but I was stressing about missing a flight & was distracted. Each time since it's been pretty apparent when following the directional signs.
I won't lie, it is a bit of a ride to the airport on the shuttle. Maybe 10-15 minutes depending on your driver but I find that even when PHX Airport is busy, their TSA has it down to a science and does a good job with people control and getting everyone through security in an efficient manner. The added time on the shuttle ride will likely not delay you. No guarantees of course but in my experience it hasn't.
With the ease of being a Hertz Gold member and the cleanliness of the vehicles, it's unlikely I'd use another rental car company when coming to Phoenix. They make it simple to keep using their services.