Overall, the stay at Fatih's place was fine and fulfilled its purpose. The location of his apartment is absolutely perfect (at least if you want some authentic and rather rough neighbourhood feeling). Also Fatih himself seems to be a nice guy.
Yet there were a couple of things that turned our stay into a slightly negative experience. Kitchen and bathroom were pretty dirty, the mattress is very uncomfortable and at times there was no gas and therefore no warm water. Seen individually, none of them is a super big deal, but in total it did leave a slightly negative impression.