We really enjoyed our stay at the flat. It is located in a comfortable residential area.
Transportation connections are great! It is about a 8-10 minute walk to the entrance of the M4 metro. And the "MetroBus" stop is about 3-5 minutes from the M4 metro entrance. Using either the M4 metro or MetroBus as our starting point we could easily get all over Istanbul. From the flat to the metro entrance is pretty easy as it is downhill, from the metro to the flat it is uphill.
Directly across the street from the flat is a grocery store and also a pharmacy (Turkish word for pharmacy is eczane). A really large shopping center is nearby which you can see from the flat, which we got to by walking to the M4 Metro entrance and then going through the metro pedestrian tunnels. The tunnels even had moving walkways in parts. So you could be at the shopping center in 15-20 minutes depending on how fast you like to walk.
Everything worked great while we were there. Demet was always responsive.