We've spent 8 days in Istanbul at Chris's apartments and were totally satisfied with the flat and neighbourhood. Appartments were comfortable and very spacious, we enjoyed the style of the furniture. Though we visited Istanbul in August it wasn't hot inside even without the fans (but there were two in case you need them).
The best thing is a balcony and the fantastic view. We enjoyed our meals sitting on the balcony and watching Bosporus.
Regarding the location, it's around 10-12 minutes walk to Istiklal and 3 minutes to the bus stop. There is also a shop near the house with a wide range of fruit and vegetables.