İsmail's place is in Ortaköy, a central neighborhood in Bosphorus. There are all kinds of shops around to have a comfortable stay. It's also reasonably close to Karaköy, Nişantaşı and Bebek, all 3 nice neighborhoods to hang out.
Apartment is small but well designed to accommodate a short to medium long stays, and İsmail and Serpil are both one message away to help with whatever you may need.