We had a lovely stay at Hotel Polski. The straff was very friendly and helpful, both arranging transport from and to the airport, and booking a trip to Auschwitz/Birkenau, including pick up service from the hotel. The hotel is perfectly placed in the Old Town, with everything within walking distance, but still quiet an peaceful.
We only had breakfast in the hotel the last day, and this was the only drawback in our experience. There was a limited continental breakfast, and a bit overprized. Still, we have a very good impression, and will certainly come back!