I returned my rental car yesterday. Check in was easy and took like 15min. I reserved a Mercedes cla which they didnt have it so they gave me a BMW X1 which i liked that as well.
The car was nice and clean with 4000 miles on it! Make sure to check the car and film it if there is any scratches or something on the vehicle. I do this on every car I rent. You have to take good care of the car otherwise you got charged for the damage!
Return also was easy and smooth.