SIXT beats most other rental companies at PHX. Yes, you will pay more, but you get what you pay for. I've rented here a few times, and they never have the exact class of vehicle you reserved, but they always make it up to you with free upgrades to vehicles in higher classes. In my experience, they've never been pushy on add-ons. The transaction is always quick and smooth as well with short lines most of the time. It's a bit of a hidden gem when you look at the line-ups at the other places at the facility. SIXT also has the best vehicles. On my most recent trip I got into a brand new BMX X4 and it was unreal. Shoutout to Scott, working the counter that day as well. Friendly and efficient employee.