I would only stay here again if improvements are made.
The location is OK, nice environment with the hotel downstairs, but please understand this apartment is actually in Ottomare Suites which is on one of the floors of the same building as Radisson Blue. The staff at Radisson Blu will not know anything about your booking. You need to go to floor 0 and not the Radisson Blu hotel reception.
When you leave the area i found that taxi drivers did not want to come back to this area to bring you back from wherever you are in Istanbul. However, the location of this apartment has good metro links.
There is a really nice place nearby with lots of cool restaurants. Its called Fişkehane and you can walk to it from the apartment. No need for a taxi.
The apartment has wifi ask the owner for the code if this information is not given beforehand or on arrival.
I made a few other recommendations to the owner to do with cleanliness in the apartment and some minor repairs, if these are taken on board this is not a bad place to stay. Good luck!