Yakup's apartment is good value for the money in Istanbul : it's very clean and well-equipped (fridge, kettle, coffee machine, ironing board and iron ...) The shower is nice and warm, and the bed comfortable. It's in a dead end so it's very quiet at night. It's within walking distance of Agya Sofia, the Blue Mosque (unfortunately it's being renovated at the moment, so not much to see), and Topkapi Palace. Yakup was very reactive to all our messages and very friendly.
The immediate neighbourhood is not very fancy nor touristy, but there are plenty of places to eat elsewhere in the city. All in all a good stay.