The landlady was indeed extremely nice and welcoming. She explained where I can find grocery shops around, gave details on public transport close by, she was great. Location is also quite good. Great neighbourhood, few restaurants (something for any taste) close by, not far from the city center and the Altstadt.
The aprtment itself was clean and tidy, there is pretty much everything you need for a short stay. I wasn´t thrilled by the fact that it was on the ground/first floor, I couldn´t get warm really, although it wasn´t all that cold outside. It says in the description that there is internet in the apartment but it turned out there wasn´t and if I wanted to I could be provided with 'a stick' for the price of 5 Eur per day.
I don´t see how the apertment will sleep 4 though. Everything you see on the pics is one room and not all that big. I would recommend it but for a short stay and for not more than 2 people.