This is by far THE BEST place you can stay in Istanbul! It's located in the youthful neighborhood of Beskistas but away from all the noise and crowd, right across a beautiful park! The view is breathtaking and the place simply has great energy. The building is right above a cafe and you have plenty of stores, pharmacy, etc.
Orkun and Cemre were fantastic! They helped me carry the super heavy luggage up the stairs and got me a SIM card that I needed. They also arranged for me to leave my bag at a winery nearby for me to pick up later. They were super fast in responding and are simply wonderful people! Highly recommend!