The best feature of this place is the location. You're right in the middle of the action of Istanbul with easy access to great food, sights, drinks, etc. The trade off is a little bit of city noise, but it's not too bad since you'll be up on the 5th floor and a bit back from the main street. As a few other reviews mention, it's a bit of a maze to get to the unit, but after a few times it becomes normal, and it's well lit with motion sensors and the building seemed very safe.
In terms of amenities, I didn't use the kitchen much so can't comment on that. There was plenty of hot water, and good water pressure in the shower, so that's good. The washing machine was nice having access to. The wifi was decent and reliable. Speeds across most of Istanbul are a bit lacking, but that's no fault of the host, it's just normal for the city. Still good enough for video streaming. Bed & pillows were ok, not great, not bad. My biggest suggestion to Murat is to add darker shades to the windows since the ones there currently let a lot of light in first thing in the morning. So if that's a concern for you, bring an eye-mask. AC was nice to have, but also just opening the windows to let the breeze in worked well most times of the day.
Overall it was a good stay but it did seem a bit pricey for what you get considering all the options in the city.