I highly recommend Gülşen's place to anyone visiting Istanbul. The view from the terrace is AMAZING. It offers beautiful views of the Bosphorus Strait, spanning from the Bosphotus bridge to the golden horn. The whole apartment is spacious for 5 people. It has 3 rooms, 2 bathrooms, and 1 toilet and a full functioning kitchen, complete with some spices, oil, coffee and tea. Overall, we had an amazing stay in Gülşen's place. The apartment is located near shops and restaurants, and it's just few mins away from Istiklal and Taksim. However, it is located in a steep, sloping street so make sure to bring comfortable shoes because you will be walking up a lot of steeps and steep streets to reach the apartment.
Gülşen was very prompt with his replies and was very accomodating with all our requests. He even helped us with our airport transfers even after our stay in his apartment. Highly recommend this airbnb!