Garen was a great host-he was easy to contact if we needed help with anything and offered local recommendations and even offered to book a Whirling Dervish show for us. He arranged our transport from the airport and helped arrange our taxi back to the airport so that it was just waiting outside at 5am when we needed it.
The apartment is good for a small group (we had 4 people). It is a 5 minute walk from Istiklal Street, where there is lots of food, shopping, and the walk down the hill to the bridge to the old city (50 minute walk away).
There is even a little farmers market right outside of the apartment on Sunday morning. I would stay here again if I came back to Istanbul.