This apartment was absolutely perfect for us. We are an international couple (turkish and spanish) who spent 15 days in here. The apartment is modern and clean. It's got a kitchen with everything you might need, including dish washer, washing machine and vacuum cleaner. Everything looks pretty new. The hot water comes instantly, the tv has a paid cable provider and is modern so you can use your own usb, hdmi connectors, etc. The wifi was enough for my partner and me work from home, including video calls, without difficulties.
The heating system works perfectly for winter. The location is also very very good. 5 minutes to Taksim square, in a normal, calm neighborhood. Those who know Istanbul are aware that it is a huge city. So having a good place to stay so near of one of the main attractions of the city is very positive.
I really don't lie saying that it is the best place I have been in, in Istanbul. And I would repeat without hesitation. Also Burak was nice and answered our texts in a few minutes.
Even the books are interesting and well chosen (for a turkish speaker, haha) . So, yeah, don't hesitate. This is your place. :)