We really loved staying in this place. Recommended.
1. Location - the apartment is 2 min walk from Galata Tower, 5 min walk to some really cool shops on the way to Karakoy and about 10 mins to Karakoy. It's also about 5 mins down to the Galata Bridge. The entrance doubles as a leather/bag shop during the day/evening with the owners very friendly. AMAZING breakfast at Smyrna Art-Gallery Cafe around the corner.
2. Terrace - there's a shared terrace on the roof with nice views of the bosphorus and mosques, with plenty of seating. The other people we encountered on the terrace we young international travelers and seemed friendly.
3. Apartment - very well equipped. The washing machine and clothes horses (x2) are perfect if you're travelling light. The exposed brickwork and artwork give it a nice vibe. Very little outside noise into the bedrooms. Nice spacious living room with views. Cute balcony from the master bedroom with blue mosque visible if you lean out. Some might find the master bedroom small as there's very little space around the bed but I really liked it!
4. Host - friendly, responsive. No issues.