Flat location is really good - close to tram, ferry, tünel, sights and cafes. Easy communication with Cüneyt and easy check-in/check-out. Expect to hear muezzin in the mornings if you have light sleep ). Also there is continuous ligth guggle sound from the pump in the bath - maybe it could be improved (you will not hear it in bedroom).
Overall this is a good place to stay in Istanbul, recommend it!