if you want to explore authentic Istanbul vibes, away from touristy spots. this is a great location. The ferry stop as well as airport transfers are 10 minutes walk from the apartment. There are plenty of shops and a market nearby where you could virtually get anything from food to souvenirs.
Murat is a very communicative and friendly host. He guided us on how to arrive to the location from the airport and was happy to recommend us places to visit. He was kind enough to store our luggage past our checkout time as well. Overall a very nice experience.
The only thing to keep in mind is that even though the ferry connection is nearby, getting to all "tourist" spots from Kadikoy takes roughly 40/50 minutes. So if you are visiting Istanbul only for those and are not so interested in the local flavor of this wonderful city, this place may not be ideal for you. But if not the case, I highly recommend this.