We stayed there for 10 days.
In general I would say it was not bad experience but with some problems.
The most important thing is an internet problem. That's aweful. First 2 days we didn't have internet at all, which was one of the most important things for me because I'm traveling and working online.
In 2 days the problem was solved, but in 3 days after the problem with internet had been repeated again. And again 1 day without the internet. I don't wanna tell anything about the owner, but I would highly recommend to change the internet provider, because that's not ok at all. The second thing - apartment wasn't that clean, and also we didn't have some amenities in the apartment (towels, hair dryer, shampoo, slippers and etc) but we got towels after requesting. In general owner and her sister were answering to our questions almost immediately.
Bad sound isolation, but it's everywhere in Istanbul seems like, TV didn't work and also we struggles with some little flies and also fridge is small.
Good things about apartment is that big enough, u can regulate a heat by your own hands, location is amazing, Bakirkoy is really good area, a lot of stores and shopping malls, restaurants and so on.
Bus till airports also near by.
In general I would call the stay is ok. If we didn't have problems with an internet connection I would highly recommend the place.