Banu is great and made a great experience and memorable trip for me and my family in my first visit to Istanbul. I, definitely, recommend her lovely apartment to my friends and will consider it for myself for my future trips to Istanbul. It's really close to the metro station with just one stop to the famous Taksim square and 4 stops to the Ground Bazar and the other historic spots. The place is also just ten minutes away from a very beautiful and huge mall of Cevahir with much many shopping store and Turkish brands and a huge food court that I've never seen such a big food court in my state in the US. It is located in a lively neighborhood with many restaurants and cafés. I recommend Döner Plus closed to the home in Rumely street (actually in Güzelbahçe in Teşvikiye). :)
Banu's apartment also has an elevator that is very helpful for everybody especially the ones like my mom who have pain and problem to walk and climb.
I also thank Banu's friend, Zeynep, for her accessibility and responsiveness as well as Banu.
Banu is an artist with many books in art especially in my major Graphic Design in her place that might be interesting for you if you are an artist too.
I bet you will have a very good experience in Banu's place if you are going to travel to Istanbul.