When you're booking pay attention to the small prints.
1) we stayed in the Studio apartment. it wasn't so clear from the images which is a studio and which is a bigger apartment. All in all it wasn't bad but we weren't prepared for it. The Studio apartment has no beds. Instead it has a sofa which you can open to a double bed and an armchair to open to a single bed.
2) you have to pay an extra PLN 105 for cleaning fee (when you sort hotels by prices, the cleaning fee is not taken into account). and you also leave a PLN 400 as deposit.
3) this is not an apartment hotel. we thought it was because it had a 3 star hotel rating. Instead it is just an apartment. it is actually more of an Air B&B type of service. Not that it's bad, but it wasn't so clear when we ordered it. After you order you receive an email with a phone number which you are supposed to call 24hr prior to check-in in order to make arrangements to receive the key. this was the first sign we had that it's an air b&b type of order (again, not that it's necessarily bad).
The owner is semi-responsive. He is partially available over the phone and rerely correspond via SMS/WhatsApp (even though he claims that we can and should contact him via WhatsApp).
The apartment is clean, the kitchen is spacious and relatively well equipped. There are some basic necessities missing: kitchen towel, kitchen paper, scotch to clean dishes, soap/shampoo, small towels in the bathroom (there is only 1 big towel per person).