If you get a chance to stay at Missy's place, don't hesitate! My husband and I just spent a wonderful 4 nights in her flat. The space isn't huge so I'd say its best for a single or a couple. The view from the terrace is beautiful and if the weather is nice you'll want to spend all evening just sipping wine and relaxing there. The flat has everything you need including laundry and she even leaves a nice basket of snacks for you to munch on.
The location couldn't be better as its just a 100m or so walk up to Istikal Street where there are many shops and restaurants. The metro, tunnel and tram as also very close to get to all the other areas of Istanbul. Her place was quiet and peaceful despite being in the heart of all the action. If you have any questions Missy responds very quickly and was kind enough to book a taxi pickup for us at 3am as we had lots of luggage and weren't sure how easy it would be to get one at the hour.
We will definitely stay again if back in Istanbul.