I used this website for car rental; I needed a car for 4 days to transport my family (2 adults 2 children + baggage) a distance of around 700 kilometers. We ageeed a larger Group C car e.g. Opel Astra wagon, Ford Focus , Renault Scenic all shown on the site. The car they brought was a Mazda 626 saloon, it was dented, had rusted holes in the bodywork, the 626 sold in Europe from 1998 - 2002, The woman who delviered the car took us to a petrol station and asked us how much fuel we wanted to put in the car. I wanted her to fill the car up so we could return it full but she made some excuse so we put in 200 zl of fuel (around £45) ; when I got in the drivers seat and turned the key the odometer reading was 285,000 km!, basically the car was at the end of its life at which point we said we did not want the car. The only other car they could offer us was an Astra hatch which we rejected as too small. They refused to refund the fuel money
So beware of using this site and related site AutoColl - note same mobile number.
The suggestion is there is a wide range of good quality cars available, in fact they have a limited number of very old, poorly maintained vehicles.