I had a relatively nice stay at Gokce & Mustafa.
The hosts are very nice & communicative. Unfortunately, while I was there, their guests upstairs were VERY VERY loud. It can also be due to the fact that noise insulation between the two flats is almost non-existent. The neighbourhood is close enough to the touristy areas, but I personally would choose to stay on the other side of the European part of Istanbul, as this area feels a little bit unsafe at night.