The apartment itself is great: very clean, modern, in a new building, good wifi, good hot water, modern appliances, comfortable bed - it's a very nice apartment. The host communicated well with us.
We were a bit unhappy with the location. Since it is near a main street, it's a bit noisy with many cars / motorcycles going by - if you're a light sleeper it can disturb you. The apartment is a ~20min walk from Taksim Square, but the neighbourhood you have to go through is not very nice. It's not too bad, but you may want to look for something a bit closer to the centre.