My wife and I stayed here for almost two months (7 weeks) through June and July, and were really pleased with our choice.
Although the property is listed as a "basement" apartment, due to the area being very hilly we were actually on the ground floor with two windows and a back door opening out onto a sunny internal courtyard.
The kitchen is well-stocked for those who like to cook and the bathroom nice (it's 1m outside the main room but it just feels like another room of the flat, we stopped even noticing that it was outside).
The property is 10-15 minutes walk away from Taksim Square (and a metro station) and around 20-25 minutes walk from the popular Galata area, so the location is ideal.
Overall, I'd definitely recommend staying here, whether you're planning to stay for a few days or a longer period (like we did).
Baran and his mum were super helpful in making our stay a pleasant one, and provided us with everything we needed during our stay.
We will definitely stay here again next time we visit the wonderful city of Istanbul!