The service is acceptable.

The rental company's staff had low English proficiency. It is unclear whether they deliberately deceived or if it was an honest mistake. We clearly stated that we only wanted to add GPS and no other extra insurance, but ended up being overcharged by nearly 200 euros. On the day of the rental, we repeatedly confirmed with the staff that the total cost was around 260 euros, but my credit card was charged over 470 euros. I believe the business practices of this rental company are very problematic. I advise others planning to visit Germany not to rent a car from this company.

It's okay!

The staff tried very hard to sell insurance at pick-up. They were unhappy when I didn't buy it and tried to scare me about potential high costs if the car had any issues. There were very few car models available, much worse than Alamo in the US.

After a small assessment, I was given an electro auto which was horrible and I needed to change after less than 24 hours. With the temperature in Frankfurt the battery does not last and the provided plug in the car for charging was a home one. It would have needed like 30 hrs for charging.