We spent ou vacation on a road trip btw Cali and Hawaii, so we rented a car three times and each times the process was really smooth. The Sunnycars website also allows to modify the booking online, which was super useful when our second flight was postponed. I appreciate that you can upload the photos of the car prior and after the rental, but I think one important thing that should be added is the time when the pix were taken. That is why I'd recommend taking pix first with your phone and then uploading them to the up, otherwise they don't get saved on the phone and the time is not visible.
We rented through Alamo and I would pont out the exceptional service of Alexander (Alex) at Lax rental center and Edward, the shuttle driver at Lax. These two truly put some dedication in their job.
I would totally recommend Sunnycars to anyone!