Okan's apartment is super clean, well taken care off and is located in very central location close to Galata Tower. The apartment is located in a small side street so it is still very quite despite its central location. We would for sure recommend Okan's apartment for a short weekend trip to Istanbul.
The only downside is that the apartment is equipped very basic so if you stay longer and want to cook at the apartment it is hard to find the needed equipment. Okan was helpful in bringing us some missing essentials but we also did not want to ask for everything that we found was missing (scissors, lighter for the stove, extra cutlery, etc.).