I just saw this thread and thought I would share my one experience. Had a 4-day rental in SNA back in March. Booked a Fiat ragtop as it was cheap and seemed like it would be more fun than a Nissan whatever. Booking process was straightforward and the host was very open and communicative. Two days before I was supposed to go, I got a message saying the car "needed work after the last renter" and was canceled. I managed to get something from Enterprise for around $100 more. I am in no hurry to rent from Turo again, at least not without a backup option.

-J.