Mehmet’s company and him are wonderful hosts!
The apartment is in my favourite neighborhood, Moda Kadıköy and I would recommend it to everyone, who wants an authentic experience, rather than a touristic, crowded like on the European side. There are tons of things to do and to go to and from here you could get anywhere, since it's a stop to all means of transportation in Istanbul.
As for the apartment itself: I felt like it's in the price range where I’d rather pay an extra 5-10 dollars, but have things like slippers, bathrobes, water, more kitchen utensils and especially a renewed shower head, for example.
I also would like to address the fact that the apartment has a boiler instead of a gas combi for the hot water. It creates a bunch of problems, some of which could be resolved. They include a really low hot water pressure (it was a struggle to have a shower) and the size of the boiler is not suitable for more than 2 people (at best) having a shower in the evening.