I rent with Sixt all the time and I had two major issues, both from their ATL location. First, they tried to hit me with $4000 in charges because I took the car out of state, I added their CEO on LinkedIn and sent him a message and explained how he will loose $10,000 in revenue each year unless they get rid of this charge (Was I violating their very...VERY fine print? Yes, was it a rip off to charge $3 a mile out of state? Yes) He sided with me and got rid of it.

The 2nd time, the ATL branch was pissed they missed out on that $4k charge and tried to hit me with a $2000 repair bill because all 4 tires were curbed. I explained to them that it is physically impossible for those wheels to have rust on them within 24 hours and that it was old damage. It will defy the laws of physics for aluminum alloy to rust within 6 months, he agreed and dropped the charges. Never rented through the ATL branch ever again.

Take lot's of pictures and look at the fine details guys!