Perfect host. Very supportive, even on stuff he was not supposed to. It got hot and we needed fans, he just bought 3 fans in a span of 2 days, and brought to us. We needed a weighing scale to check our luggages before flying back home, he bought a scale and gave it to us. The scale was not working, so he went to the whole trouble again, to buy another one, check it, bring it to us, and return the previous one, all in time for us to be sure about the weight of our luggage.
The apartment is in the heart of Istanbul. 5 min walk to the shore, 5 min walk to the famous shopping and sightseeing street in Istannul; Taksim square and Istiklal (if I am right about the spelling) street. If you are in Istanbul for the social life, never sleeping city and night life, cafes, restaurants, parties and such, this is the perfect location.
Checking in and out was flexible to our needs and perfectly smooth. He even helped us contact transportation to and from airport, suggested best restaurants, shopping malls, etc. for us.