We just returned from two weeks in Germany, renting a car as we left Berlin.
We took the advice in these articles -
https://www.ricksteves.com/travel-tips/transportation/booking-a-car
and here
https://www.ricksteves.com/travel-tips/transportation/car-rental-cdw
We rented from Auto Europe, a rental car consolidator recommended by Rick (I'm sure he gets a referral via the link). The price I found through this link beat others by a mile.
Auto Europe provided the car through Europcar.
The process was easy, we had a great car (a brand new diesel Skoda Octavia Wagon with only 10km, navigation no extra charge) and had no problems at all. This vehicle was considered a mid-size - we chose it so that our daughter and luggage would have plenty of room in the back.
Things that helped:
- We scouted out Europcar rental agency locations that were geographically convenient and offered the open/close hours we needed. We picked up our car at a non-airport location near our pension in Berlin, then dropped off at the Dusseldorf Airport. We were not charged an extra fee.
- Pick up your car on time. The morning of our scheduled pick up, I called to let Europcar know we were running a 30 minutes late, and they advised that they would make a point of holding the car for us since it was within a reasonable time frame. The clerk implied that if we were outside the 60 minute window, they would not have have held the car for us.
- We pre-printed the credit card Letter of Coverage and brought it with us to Europcar desk, refusing all other insurance. This letter was accepted easily, although the clerk still did try to sell us coverage.
- At drop off in Dusseldorf the people in the garage area who processed our return did not have the ability to print out their acknowledgement that we had returned the car with no damage, so we walked inside to the counter to get the acknowledgement.
If we hadn't moved around so much, we may have considered just sticking with trains. As it is, we hopped all around "Lutherland" and Southern Bavaria with ease. Turns out we put about 2100km on that new car!