We were a group of four and have stayed in the apartment for 10 days and I must say it was a very good experience.
First of all the apartment is exactly the same as the pictures. Recently renovated and very clean.
There is one living room with a kitchenette, a small table, a TV set and a convertible sofa; and one bedroom with a king size bed, a TV set, a closet, and a small safe box; and a bathroom. Both bed and sofa are comfortable. The sofa bed was a bit weird but it was acceptable. The air conditioner unit is in the living room so if you close the bedroom door it may get warm. But during our stay the weather was fine and leaving the window open was OK.
The bathroom was very clean. There were towels, soap, shampoo and a hair dryer. And we could get new and clean towels whenever needed.
The kitchenette in the living room has a mini fridge, an electric oven, a microwave, an electric kettle and some plates, glasses, pans and...
The WiFi was OK. We had trouble connecting for two days but then it got fixed and it was fine.
In general the apartment is like a small motel. All the apartments in the building are for rent and there is a concierge.
We met our host Nida once. She was very nice and kind and gave us some advice on where to go and visit. The rest of the time Mehmet was there. He was also very nice and whenever we needed anything we could tell him. There was a washing machine in the concierge room so we had to take our laundry there and Mehmet would take care of them and brought them all clean and folded to our room.
Although the house is completely renovated, the neighborhood is quiet old and poor and at first it might be a bit disappointing but when you get used to it, it's not that bad at all. It is safe and you can walk even late at night. There are some shops and grocery stores and cafés nearby. There is a mini Carrefour close by and if you are there on a Sundays you may be surprised that the whole street will turn into an amazing local Sunday market.
Great location I can say. Close to Istiklal Street (about 5 mins walking) and Taksim square and metro station (about 15 mins).
In general it was a very pleasant stay, good location and reasonable price. Istanbul is a wonderful city and the apartment is highly recommended.