I stayed in Mustafa's house for 10 days. Overall, I was very satisfied and recommend it. There are some points as pros and cons.
Pros:
1- The location is great, 5 min to Taksim, close to the supermarket.
2- It is pretty quiet compared to the nearby streets where you may hear loud music. At Mustafa's place, I could not hear club music or call for Pray .
3- It is great for two people and you can find all utensils.
4- Fewer stairs compared to many other places; a semi-basement with windows.
5-There is a washing machine, microwave, and oven if you need them.
6- The shower was very good.
Cons:
1- Still there is a slope to go from home to Taksim but it is not very hard to climb, elderly people will have difficulty. Most of Istanbul is up or downhill.
2-I could not find an iron, or study table, and the dining table is missing. You can still eat on the coffee table.
3- I wish there was a closet to hang the clothes or put some stuff in it
4- The internet signal in the bedroom is very week.