First time renting in Poland (had previous experience from Europe and US) and it went super smoothly, very nice brand new car, clean, no problems at the check out, friendly staff. Like with any car rental, make sure you read all the small print and know all the insurance rules! They are quite strict on pick up and drop off times so make sure you put them in correctly at the online booking (the car will only wait 1h from the provided booking time). Also, don't forget the pin to your credit card!