Engin is a great host and answered every request we had very quickly. We stayed for a month and he provided us with housekeeping 2x a week. The apartment is comfortable and has a very good shower. My only complaint is about the internet: if you're planning to work from home, bear in mind the WiFi is very unstable and slow. Although Engin was super helpful and even installed a router inside the apartment just for us (before it was those shared routers for the entire building) the WiFi still was very bad during our entire stay :(
But, other than that, great apartment, great price, and great location! 2 minutes walking from Taksim square, several local restaurants close by (look for the Falafel House) and also a very nice gym located inside a nearby hotel).
Final say: If you won't need to work from the apt, you should definitely book it!