I stayed for three nights. I will start with the pros: the communication with Ahmet was great, he always responds right away and is very helpful. There is a 24 hour reception for the building and they are so helpful and make you feel safe. The location is outstanding, since you are 15 minutes from Taksim, Karakoy (where you can take boats to the other side) and less than 10 minutes walk from metro, tram and other transportation. The place was very clean, great shower, an elevator and fast wifi!
Cons: its a bit smaller than the pictures show, it needs a few more amenities (theres a boiler but no cups to drink anything, no basic tea, coffee, sugar, water, no extra blanket or pillow). All in all, would stay there again for sure.