I stayed at Ralf's apartment for 3 weeks. It was great experience, the apartment is very spacious, well equipped, comfortable and has lots of natural lights. the location is quite good, 10 minutes by walk from there you have connections to everywhere, but also a tram very close. The only "bad" thing is that it is sometimes noisy from neighbours as it's old building, but it's not a big issue.
I was very nice welcomed with some food in fridge which was very helpful as it was Sunday. I would recommend Ralf's apartment to anyone.