The apartment is very professionally managed and in excellent condition. Trash valet service (twice daily), weekly cleaning, concierge service, off street/ valet parking... The staff were extremely warm and caring as well, always willing to help and greeting with a smile. I stayed for 7 weeks and would love to go back ASAP.
***About the location:
1) Petra Roasting Co. (aka Petra Cafe) is within 120 meters from the apartment and is reputed as the best cafe in Istanbul with amazing coffee and food. Great place to meet new people.
2) Nisantasi and Maslak are only 7 to 8 minutes away (20 min during rush hour). Besiktas bar district is within 5 minutes (go straight down on the Barbaros Boulevard), Taksim/ Kadikoy are usually 15 to 20 minutes away.
3) My tip would be that this location is ideal to get around by car or taxi but there are also plenty of bus routes. Metro station (Gayrettepe Station) was a bit far on the other hand (15 to 20 minutes away on foot).