I rented at LAX last week. Contrary to previous reports, everyone at pick-up and drop-off was extremely friendly.
Had a PCAR reservation and was offered a BMW 228, Volvo S60, or (for $10/day more) an Audi A4. Took the BMW coupe and was very happy. Sixt's rates were great too - Avis and Hertz always want well over $100/day for any decent foreign car, but I got a well-outfitted BMW for the same price Avis would have charged to put me in some awful, high mileage Chevy wind-up car with no features. Sixt also charges slightly less for liability insurance than Avis (can't figure out how much Hertz charges), which is good since it's a daily charge (and required in CA for those of us who don't have car insurance otherwise).
I arrived on foot, but took the shuttle from the Renaissance back. The shuttle situation is not great - it was totally full and you have to stop at another hotel on the way to the airport. That wouldn't stop me from renting with Sixt again, but you need to build in extra time for the stop, and the fact that the shuttle only runs a couple times an hour. An older couple on the shuttle took a 10:30 shuttle for an 11:30 flight and were sweating it the whole way (they arrived at the Delta terminal around 10:50).
Looking forward to renting with Sixt again.