We stayed in Aybalas place for a full 2 weeks and we loved it. The flat is in a great area from which you can reach all of Istanbul easily by foot or with Tram/Metro, yet it is in a bit of a back-street so its very quiet at night which is great.
The flat is spacious and is fully equipped, good internet for working.
Aybala is very nice, was very flexible with our arrival and check out times and gave us a bunch of tips on how to have a great time in the city. :))) all good