We had a great stay at Kasia's place. The apartment is modern, very clean and well equipped, in a nice and quiet street with a little park right around the corner where you can drink coffee. Kasia was very friendly and flexible with check-in times.
The only little issue we had was the sleeping couch which was hard to pull out, even with two people, and which blocked the door to the bedroom when pulled out. When we finally managed to pull it out, it was quite comfortable to sleep on, though.
All in all, I definitely recommend Kasia's place.