We had a great stay at the apartment. Clean, comfortable (for two people) and most of all with truly spectacular views. The location is also great, close to both tram and metro stations, and close enough by foot to the historical area. It also has better evening and nightlife than the historical area.
Manzara also provided us with airport transportation, which is convenient because taxi pickup can be a bit chaotic at the airport and it is not easy to arrive by car to the apartment because of the narrow streets in the old town. In fact, the car dropped us at the Galata Tower's square, where we met someone from Manzara that took us to the apartment (2' walk), and also helped us carrying suitcases into the 6th floor apartment w/o elevator, which was nice when you carry 20+kg suitcases!
Gerrit from Manzara was very helpful and supportive before and during our stay, providing useful tips and answering our questions quickly, both through email and whatsapp.
The apartment was as advertised, except that it did not have a microwave. As compensation, they allowed us to extend our stay until the end of the checkout day, which was great to store suitcases during the last day and then meet for the airport trip. The apartment also has a washing machine in the kitchen area that we did not use. We would have much preferred to have a dishwasher instead.
All in all a great stay. We definitely recommend the apartment as well as Manzara, and we will definitely stay again with them in our next trip to Istambul.