Okay so we had to leave the appartment because of constant water shortage, the host was gracious enough to refund the remaining days without any troubles and i'll try to give the most objective review i can :
PRO'S :
*The location is excellent. Really you're in the middle of the coolest part of taksim.
*The apartment is really silent, in spite of being in such an active part. Except the seagul sounds (which i love!) you don't feel like your in the middle of Kadikoy.
*The decoration is kind of elegant and artsy.
CON'S :
*First surprise when we arrive : a terrible and strong sewage odour. We message the host and they said that it's du to the windy days and it's normal in Kadikoy. The issue is that i already spent a lot of time in the neighborhood and it never happened before but i was willing to take they words for face value and trust that it will go on it's own. During two weeks it never stopped, forcing us to have the bathroom closed at all time and even then you could smell it sometime. The bad part is that somebody complain about it just before we arrived but they didn't told us.
*The wifi is shared between you and the host and the box is not in the apt. Not a big deal for most people but i feel they should have disclosed it. It did work okay.
*The water cut dry 5 times during our stay. Like nothing going out for 30 minutes in the best case, over 48h of going between "not a drop" and "some", which made took the decision to leave. 3 days without a proper shower 🤧.
*Communication started good but then was slow, dismissive and upfront ignoring us at time. When we leaved, it seem like they were mad at us 🧐
*Lack of essentials for a long stay : we had to wait more than one week to have a second set of keys, there were no spoons, not a second set of sheets, dishcloth. the bed was busted and hard.
CONCLUSION : for a few days in Kadikoy i think it's ok. It's not suitable for a long stay.