Great place! The location is the best...literally 2 mins walk to the blue mosque. Hagha Sophia is 5 mins away. Lots of restaurants and there is a mini market right across from the apartment. The place is quite huge - we were a family of 5 and had lots of room and beds. Ali was a great host - he took care of everything including the pick and drop off to the airport. I highly recommend using that service and it is not that costly. Good heating and cooling in the apartment. Very safe building and the apartment is very secure. Checkin and Checkout was very easy and very well taken care of. Will certainly stay there again if we make it back to Istanbul.
Quick Tip: Avoid buying items (lamps/deserts etc)at the shops in the grand bazaar or the streets by the apartment streets - head to to the spice market and the nearby market shops to it as they are the best priced place that we found.