It's only fair if good experiences are registered as well.
I actually showed up 30 minutes in advance to account for the time i'd spend arguing over who knows what issues (as i had read in countless reviews) but to my surprise the process couldn't have been smoother.
Funny enough there was a scratch on one of the rims which i hadn't notice when i picked up the car, but i had taken pictures and Wesley (the Sixt employee) reassured me i wouldn't have to pay anything considering the proof.
All in all flawless drop. 3 minutes and a shake of hand.