My friend and I stayed at Tim's for two nights. We only saw him, when we checked out, but he was still helpful during our stay and seems very friendly. He answered to all our questions (via texts) very quickly, which was quite useful.
The apartment itself was a typical German student apartment share and as we are German students ourselves, we felt very comfortable there. It is nicely located, directly at a metro station, which made traveling in the city easy.
Thanks Tim, see you next time!