They never answer the phone.

We wasted nearly an hour returning the car at the German airport, almost causing us to miss our flight. Other rental companies were very friendly; you could just leave the car and go. However, one staff member from this company ignored us, saying the car came from the Czech Republic and he wasn't responsible. We asked him who to approach, and he kept saying it wasn't his problem with a very bad attitude. We had to queue at the front desk, and they told us to park the car in the parking lot and inform a staff member. We mentioned that no one paid attention to us. Finally, another rental company staff helped us resolve the issue.

Picking up and returning the car was very convenient, and the staff's attitude was very good.

I rented a GPS from the store for 8 euros per day, but it had no signal when turned on. The reception said it would work outdoors without issue. However, it didn't work outdoors either. I drove a bit but still no signal, so I had to go back to exchange it. Everything else was fine.

Like: I liked that it was possible to get a great last minute deal within my budget. The reservation desk guy was helpful and friendly. We got the car as scheduled with no delays or waiting.
Dislike: We booked VW golf class and got a Seat (not sure which make). It was kind of a nice upgrade. However, this car has very uncomfortable front seats. It has nothing to do with Budget, just a thing to keep in mind.